Processes for separation of fluoroolefins from hydrogen fluoride by azeotropic distillation

ABSTRACT

The present disclosure relates to a process for separating a fluoroolefin from a mixture comprising hydrogen fluoride and fluoroolefin, comprising azeotropic distillation both with and without an entrainer. In particular are disclosed processes for separating any of HFC-1225ye, HFC-1234ze, HFC-1234yf or HFC-1243zf from HF.

CROSS REFERENCE(S) TO RELATED APPLICATION(S)

This application claims the priority benefit of U.S. ProvisionalApplication No. 60/839,737, filed Aug. 24, 2006.

BACKGROUND INFORMATION

1. Field of the Disclosure

This disclosure relates in general to processes for separating HF fromfluoroolefins.

2. Description of the Related Art

The chemical manufacture of fluoroolefins may produce mixtures of thedesired fluoroolefins and hydrogen fluoride (HF). The separation offluoroolefins and HF is not always easily accomplished. Existing methodsof distillation and decantation are very often ineffective forseparation of these compounds. Aqueous scrubbing may be effective, butrequires the use of large amounts of scrubbing solutions and producesexcessive waste as well as wet product that must then be dried.Therefore, there is a need for new methods of separating HF fromfluoroolefins.

SUMMARY

The present disclosure provides a process for separating a mixturecomprising HF and fluoroolefin, said process comprising: a) feeding thecomposition comprising HF and fluoroolefin to a first distillationcolumn; b) removing an azeotrope composition comprising HF andfluoroolefin as a first distillate and either i) HF or ii) fluoroolefinas a first column bottoms composition; c) condensing the firstdistillate to form two liquid phases, being i) an HF-rich phase and ii)a fluoroolefin-rich phase; and d) recycling a first liquid phaseenriched in the same compound that is removed as the first columnbottoms, said first liquid phase being either i) HF-rich phase or ii)fluoroolefin-rich phase, back to the first distillation column.

Also disclosed is a process for separating a fluoroolefin from a mixturecomprising hydrogen fluoride and said fluoroolefin, wherein saidfluoroolefin is present in a concentration greater than the azeotropeconcentration for hydrogen fluoride and said fluoroolefin, said processcomprising: a) feeding said mixture comprising hydrogen fluoride andsaid fluoroolefin to a first distillation column; b) removing anazeotrope composition comprising hydrogen fluoride and fluoroolefin as afirst distillate from the first distillation column; c) recoveringfluoroolefin essentially free of hydrogen fluoride as a first bottomscomposition from the first distillation column; d) condensing the firstdistillate to form two liquid phases, being i) a hydrogen fluoride-richphase and ii) a fluoroolefin-rich phase; and e) recycling thefluoroolefin-rich phase to the first distillation column.

Also provided is a process for separating hydrogen fluoride from amixture comprising hydrogen fluoride and a fluoroolefin, whereinhydrogen fluoride is present in a concentration greater than theazeotrope concentration for hydrogen fluoride and said fluoroolefin,said process comprising: a) feeding said mixture comprising hydrogenfluoride and fluoroolefin to a first distillation column; b) removing anazeotrope or azeotrope-like composition comprising fluoroolefin and HFas a first distillate from the first distillation column; c) recoveringhydrogen fluoride essentially free of fluoroolefin as a first bottomscomposition from the first distillation column; d) condensing the firstdistillate to form two liquid phases, being a fluoroolefin-rich phaseand a hydrogen fluoride-rich phase; and e) recycling the HF-rich phaseto the first distillation column.

Also provided is a process for the purification of a fluoroolefin from amixture comprising fluoroolefin and HF, wherein said fluoroolefin ispresent in said mixture in a concentration greater than the azeotropeconcentration for said fluoroolefin and HF, said process comprising: a)adding an entrainer to the mixture comprising fluoroolefin and HF thusforming a second mixture; b) distilling said second mixture in a firstdistillation step to form a first distillate composition comprising HF,fluoroolefin, and entrainer, and a first bottoms composition comprisingfluoroolefin; c) condensing said first distillate composition to formtwo liquid phases, being i) an HF-rich phase and ii) an entrainer-richphase; and d) optionally recycling the fluoroolefin-rich phase back tothe first distillation step.

Also provided is a process for the purification of HF from a mixturecomprising a fluoroolefin and HF, wherein HF is present in aconcentration greater than the azeotrope concentration for HF and saidfluoroolefin, said process comprising: a) adding an entrainer to themixture comprising fluoroolefin and HF thus forming a second mixture; b)distilling said second mixture in a first distillation step to form afirst distillate composition comprising HF, entrainer, and fluoroolefin,and a first bottoms composition comprising HF; c) condensing said firstdistillate composition to form two liquid phases, being i) anentrainer-rich phase and ii) an HF-rich phase; and d) optionallyrecycling the HF-rich phase back to the first distillation step.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated in the accompanying figures to improveunderstanding of concepts as presented herein.

FIG. 1 is an illustration of one embodiment of an azeotropicdistillation for the separation of HF and a fluoroolefin with no addedentrainer.

FIG. 2 is an illustration of one embodiment of an azeotropicdistillation for the separation of HF and a fluoroolefin with an addedentrainer.

FIG. 3 is an illustration of one embodiment of a process to separate atleast one of HFC-236ea and HFC-236cb from a mixture comprisingHFC-1225ye, HF and said at least one of HFC-236ea and HFC-236cb viaazeotropic distillation wherein HFC-1225ye acts as an entrainer followedby a process in which HFC-1225ye and HF are separated from a mixturecomprising HFC-1225ye and HF, but now substantially free of HFC-236eaand/or HFC-236cb, by azeotropic distillation without the addition ofanother chemical compound to function as an entrainer.

FIG. 4 is an illustration of one embodiment of a process to separateHFC-1225ye and at least one of HFC-236ea and HFC-236cb from a mixturecomprising HFC-1225ye, HF and said at least one of HFC-236ea andHFC-236cb via azeotropic distillation wherein a supplemental entraineris fed to the distillation.

FIG. 5 is an illustration of one embodiment of a process to separate atleast one of HFC-236ea and HFC-236cb from a mixture comprisingHFC-1225ye, HF and said at least one of HFC-236ea and HFC-236cb viaazeotropic distillation wherein HFC-1225ye acts as an entrainer followedby a process in which HFC-1225ye and HF are separated from a mixturecomprising HFC-1225ye and HF, but now substantially free of HFC-236eaand/or HFC-236cb, by azeotropic distillation with an added entrainer.

FIG. 6 illustrates another embodiment of the process shown in FIG. 3wherein the two-phase mixture leaving the condenser of the first columnis decanted and separated into HFC-1225ye-rich and HF-rich streams whichare fed to the HFC-1225ye and HF columns, respectively.

FIG. 7 illustrates another embodiment of the process shown in FIG. 5wherein the two-phase mixture leaving the condenser of the first columnis decanted and separated into HFC-1225ye-rich and HF-rich streams whichare fed to the HFC-1225ye and HF columns, respectively.

FIG. 8 illustrates another embodiment of the process shown in FIG. 6,wherein the three columns, 20, 110, and 220, share one decanter.

Skilled artisans appreciate that objects in the figures are illustratedfor simplicity and clarity and have not necessarily been drawn to scale.For example, the dimensions of some of the objects in the figures may beexaggerated relative to other objects to help to improve understandingof embodiments.

DETAILED DESCRIPTION

Many aspects and embodiments have been described above and are merelyexemplary and not limiting. After reading this specification, skilledartisans appreciate that other aspects and embodiments are possiblewithout departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments willbe apparent from the following detailed description, and from theclaims.

1. Definitions and Clarification of Terms

Before addressing details of embodiments described below, some terms aredefined or clarified.

By azeotropic or azeotrope composition is meant a constant-boilingmixture of two or more substances that boils at a constant compositionand thus behaves as a single substance. Constant-boiling compositionsare characterized as azeotropic because they exhibit either a maximum orminimum boiling point, when compared with the boiling points of theindividual components. Azeotropic compositions are also characterized bya minimum or a maximum in the vapor pressure measurements relative tothe vapor pressure of the neat components in a PTx cell as a function ofcomposition at a constant temperature. For homogenous azeotropes, wherethe vapor phase is in equilibrium with a single liquid phase, thecompositions of the vapor and liquid phases are identical. However, forheterogeneous azeotropes, where the vapor phase is in equilibrium withtwo liquid phases, all three equilibrium phases can have different, butconstant, compositions.

As used herein, the term “azeotrope-like composition” (also commonlyreferred to as a “near azeotropic composition”) means a constantboiling, or substantially constant boiling liquid admixture of two ormore substances that behaves as a single substance. One way tocharacterize an azeotrope-like composition is that the composition ofthe vapor produced by partial evaporation or distillation of the liquiddoes not change substantially throughout the partial evaporation ordistillation. Similarly, the composition of the liquid phase or phasespresent does not change substantially during the partial evaporation ordistillation. That is, the admixture boils/distills/refluxes withoutsubstantial composition change. This is to be contrasted withnon-azeotrope-like compositions in which the liquid composition changesto a substantial degree during boiling or evaporation. Another way tocharacterize an azeotrope-like composition is that the bubble pointvapor pressure of the composition and the dew point vapor pressure ofthe composition at a particular temperature are substantially the same.Herein, a composition is considered to be azeotrope-like if thedifference in dew point pressure and bubble point pressure is less thanor equal to 3 percent (based upon the bubble point pressure).

By high-boiling azeotrope is meant that an azeotropic or azeotrope-likecomposition boils at a higher temperature at any given pressure than anyone of the compounds that comprise it would separately boil at thatpressure. Alternately, by high-boiling azeotrope is meant any azeotropicor azeotrope-like composition that has a lower vapor pressure at anygiven temperature than any one of the compounds that comprise it wouldseparately have at that temperature.

By low-boiling-azeotrope is meant that an azeotropic or azeotrope-likecomposition boils at a lower temperature at any given pressure than anyone of the compounds that comprise it would separately boil at thatpressure. Alternately, by low-boiling azeotrope is meant any azeotropicor azeotrope-like composition that has a higher vapor pressure at anygiven temperature than the vapor pressure of any one of the compoundsthat comprise the azeotrope would separately have at that temperature.

It is possible to characterize an azeotropic or azeotrope-likecomposition as a substantially constant-boiling admixture that mayappear under many guises, depending upon the conditions chosen, byseveral criteria:

-   -   The composition can be defined as an azeotrope of two compounds        because the term “azeotrope” is at once both definitive and        limitative, and requires effective amounts of those two or more        compounds for this unique composition of matter which can be a        constant-boiling composition.    -   It is well known by those skilled in the art, that, at different        pressures, the composition of a given azeotrope or        azeotrope-like composition will vary at least to some degree, as        will the boiling point temperature. Thus, an azeotropic or        azeotrope-like composition of two compounds represents a unique        type of relationship but with a variable composition which        depends on temperature and/or pressure. Therefore, compositional        ranges, rather than fixed compositions, are often used to define        azeotropes and azeotrope-like compositions.    -   An azeotrope or azeotrope-like composition of two compounds can        be characterized by defining compositions characterized by a        boiling point at a given pressure, thus giving identifying        characteristics without unduly limiting the scope of the        invention by a specific numerical composition, which is limited        by and is only accurate as the analytical equipment available.

It is recognized in the art that both the boiling point and the weight(or mole) percentages of each component of the azeotropic compositionmay change when the azeotrope or azeotrope-like liquid composition isallowed to boil at different pressures. Thus, an azeotropic or anazeotrope-like composition may be defined in terms of the uniquerelationship that exists among components or in terms of the exactweight (or mole) percentages of each component of the compositioncharacterized by a fixed boiling point at a specific pressure.

As used herein, the term “azeotrope” is meant to refer to azeotropecompositions and/or azeotrope-like compositions.

By entrainer is meant any compound that, when added to a first mixture,forms one or more azeotropes with the components of the mixture tofacilitate separation of the components of the mixture. As used herein,the terms “entrainer” and “entraining agent” are used interchangeablyand are to be interpreted as having identical meaning.

The process equipment for all the processes disclosed herein and theassociated feed lines, effluent lines and associated units may beconstructed of materials resistant to hydrogen fluoride. Typicalmaterials of construction, well-known to the art, include stainlesssteels, in particular of the austenitic type, and the well-known highnickel alloys such as Monel® nickel-copper alloys, Hastelloy® nickelbased alloys and Inconel® nickel-chromium alloys.

By azeotropic distillation is meant a process in which a distillationcolumn is operated under conditions to cause one or more azeotropic orazeotrope-like composition to form, and thereby facilitates theseparation of the components of the mixture. Azeotropic distillationsmay occur where only the components of the mixture to be separated aredistilled, or where an entrainer is added that forms an azeotrope withone or more of the components of the initial mixture. Entrainers thatact in this manner, that is to say, that form an azeotrope with one ofmore of the components of the mixture to be separated thus facilitatingthe separation of those components by distillation, are more commonlycalled azeotroping agents or azeotropic entrainers.

In conventional or azeotropic distillations, the overhead or distillatestream exiting the column may be condensed using conventional refluxcondensers. At least a portion of this condensed stream can be returnedto the top of the column as reflux, and the remainder recovered asproduct or for optional processing. The ratio of the condensed materialwhich is returned to the top of the column as reflux to the materialremoved as distillate is commonly referred to as the reflux ratio. Thecompounds and entrainer exiting the column as distillate or distillationbottoms stream can then be passed to a stripper or second distillationcolumn for separation by using conventional distillation, or may beseparated by other methods, such as decantation. If desired, theentrainer may then be recycled back to the first distillation column forreuse.

The specific conditions which can be used for practicing the inventiondepend upon a number of parameters, such as the diameter of thedistillation column, feed points, number of separation stages in thecolumn, among others. In one embodiment, the operating pressure of thedistillation system may range from about 5 to 500 psia, in anotherembodiment, about 20 to 400 psia. Normally, increasing the reflux ratioresults in increased distillate stream purity, but generally the refluxratio ranges between 1/1 to 200/1. The temperature of the condenser,which is located adjacent to the top of the column, is normallysufficient to substantially fully condense the distillate that isexiting from the top of the column, or is that temperature required toachieve the desired reflux ratio by partial condensation.

The problems associated with conventional distillation can be solved bya distillation process using entrainers. The difficulty in applying thismethod is that there is no known way, short of experimentation, ofpredicting which if any compound will be an effective entrainer.

As used herein, by “essentially free of” is meant that a compositioncontains less than about 100 ppm (mole basis), less than about 10 ppm orless than about 1 ppm, of the specified component. If a composition isessentially free of more than one component, then the totalconcentration of those components is less than about 100 ppm, less thanabout 10 ppm, or less than about 1 ppm.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

Also, use of “a” or “an” are employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of theelements use the “New Notation” convention as seen in the CRC Handbookof Chemistry and Physics, 81^(st) Edition (2000-2001).

Hydrogen fluoride (HF, anhydrous) is a commercially available chemicalor can be produced by methods known in the art.

The term “fluoroolefin” is intended to mean a compound comprising carbonand fluorine and optionally hydrogen that additionally comprises atleast one double bond.

In one embodiment, fluoroolefins comprise compounds with 2 to 12 carbonatoms, in another embodiment the fluoroolefins comprise compounds with 3to 10 carbon atoms, and in yet another embodiment the fluoroolefinscomprise compounds with 3 to 7 carbon atoms. Representativefluoroolefins include but are not limited to all compounds as listed inTable 1, Table 2, and Table 3.

The present invention provides fluoroolefins having the formula E- orZ—R¹CH═CHR² (Formula I), wherein R¹ and R² are, independently, C₁ to C₆perfluoroalkyl groups. Examples of R¹ and R² groups include, but are notlimited to, CF₃, C₂F₅, CF₂CF₂CF₃, CF(CF₃)₂, CF₂CF₂CF₂CF₃, CF(CF₃)CF₂CF₃,CF₂CF(CF₃)₂, C(CF₃)₃, CF₂CF₂CF₂CF₂CF₃, CF₂CF₂CF(CF₃)₂, C(CF₃)₂C₂F₅,CF₂CF₂CF₂CF₂CF₂CF₃, CF(CF₃)CF₂CF₂C₂F₅, and C(CF₃)₂CF₂C₂F₅. In oneembodiment the fluoroolefins of Formula I, have at least about 4 carbonatoms in the molecule. In another embodiment, the fluoroolefins ofFormula I have at least about 5 carbon atoms in the molecule. Exemplary,non-limiting Formula I compounds are presented in Table 1.

TABLE 1 Code Structure Chemical Name F11E CF₃CH═CHCF₃1,1,1,4,4,4-hexafluorobut-2-ene F12E CF₃CH═CHC₂F₅1,1,1,4,4,5,5,5-octafluoropent-2-ene F13E CF₃CH═CHCF₂C₂F₅1,1,1,4,4,5,5,6,6,6-decafluorohex-2-ene F13iE CF₃CH═CHCF(CF₃)₂1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene F22EC₂F₅CH═CHC₂F₅ 1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene F14ECF₃CH═CH(CF₂)₃CF₃ 1,1,1,4,4,5,5,6,6,7,7,7-dodecafluorohept-2-ene F14iECF₃CH═CHCF₂CF—(CF₃)₂1,1,1,4,4,5,6,6,6-nonafluoro-5-(trifluoromethyl)hex-2-ene F14sECF₃CH═CHCF(CF₃)—C₂F₅1,1,1,4,5,5,6,6,6-nonfluoro-4-(trifluoromethyl)hex-2-ene F14tECF₃CH═CHC(CF₃)₃1,1,1,5,5,5-hexafluoro-4,4-bis(trifluoromethyl)pent-2-ene F23EC₂F₅CH═CHCF₂C₂F₅ 1,1,1,2,2,5,5,6,6,7,7,7-dodecafluorohept-3-ene F23iEC₂F₅CH═CHCF(CF₃)₂1,1,1,2,2,5,6,6,6-nonafluoro-5-(trifluoromethyl)hex-3-ene F15ECF₃CH═CH(CF₂)₄CF₃ 1,1,1,4,4,5,5,6,6,7,7,8,8,8-tetradecafluorooct-2-eneF15iE CF₃CH═CH—CF₂CF₂CF(CF₃)₂ 1,1,1,4,4,5,5,6,7,7,7-undecafluoro-6-(trifluoromethyl)hept-2-ene F15tE CF₃CH═CH—C(CF₃)₂C₂F₅1,1,1,5,5,6,6,6-octafluoro-4,4-bis(trifluoromethyl)hex-2- ene F24EC₂F₅CH═CH(CF₂)₃CF₃ 1,1,1,2,2,5,5,6,6,7,7,8,8,8-tetradecafluorooct-3-eneF24iE C₂F₅CH═CHCF₂CF—(CF₃)₂ 1,1,1,2,2,5,5,6,7,7,7-undecafluoro-6-(trifluoromethyl)hept-3-ene F24sE C₂F₅CH═CHCF(CF₃)—C₂F₅1,1,1,2,2,5,6,6,7,7,7-undecafluoro-5- (trifluoromethyl)hept-3-ene F24tEC₂F₅CH═CHC(CF₃)₃1,1,1,2,2,6,6,6-octafluoro-5,5-bis(trifluoromethyl)hex-3- ene F33EC₂F₅CF₂CH═CH—CF₂C₂F₅1,1,1,2,2,3,3,6,6,7,7,8,8,8-tetradecafluorooct-4-ene F3i3iE(CF₃)₂CFCH═CH—CF(CF₃)₂1,1,1,2,5,6,6,6-octafluoro-2,5-bis(trifluoromethyl)hex-3- ene F33iEC₂F₅CF₂CH═CH—CF(CF₃)₂ 1,1,1,2,5,5,6,6,7,7,7-undecafluoro-2-(trifluoromethyl)hept-3-ene F16E CF₃CH═CH(CF₂)₅CF₃1,1,1,4,4,5,5,6,6,7,7,8,8,,9,9,9-hexadecafluoronon-2-ene F16sECF₃CH═CHCF(CF₃)(CF₂)₂C₂F₅ 1,1,1,4,5,5,6,6,7,7,8,8,8-tridecafluoro-4-(trifluoromethyl)hept-2-ene F16tE CF₃CH═CHC(CF₃)₂CF₂C₂F₅1,1,1,6,6,6-octafluoro-4,4-bis(trifluoromethyl)hept-2-ene F25EC₂F₅CH═CH(CF₂)₄CF₃1,1,1,2,2,5,5,6,6,7,7,8,8,9,9,9-hexadecafluoronon-3-ene F25iEC₂F₅CH═CH—CF₂CF₂CF(CF₃)₂ 1,1,1,2,2,5,5,6,6,7,8,8,8-tridecafluoro-7-(trifluoromethyl)oct-3-ene F25tE C₂F₅CH═CH—C(CF₃)₂C₂F₅1,1,1,2,2,6,6,7,7,7-decafluoro-5,5- bis(trifluoromethyl)hept-3-ene F34EC₂F₅CF₂CH═CH—(CF₂)₃CF₃1,1,1,2,2,3,3,6,6,7,7,8,8,9,9,9-hexadecafluoronon-4-ene F34iEC₂F₅CF₂CH═CH—CF₂CF(CF₃)₂ 1,1,1,2,2,3,3,6,6,7,8,8,8-tridecafluoro-7-(trifluoromethyl)oct-4-ene F34sE C₂F₅CF₂CH═CH—CF(CF₃)C₂F₅1,1,1,2,2,3,3,6,7,7,8,8,8-tridecafluoro-6- (trifluoromethyl)oct-4-eneF34tE C₂F₅CF₂CH═CH—C(CF₃)₃ 1,1,1,5,5,6,6,7,7,7-decafluoro-2,2-bis(trifluoromethyl)hept-3-ene F3i4E (CF₃)₂CFCH═CH—(CF₂)₃CF₃1,1,1,2,5,5,6,6,7,7,8,8,8-tridecafluoro- 2(trifluoromethyl)oct-3-eneF3i4iE (CF₃)₂CFCH═CH—CF₂CF(CF₃)₂ 1,1,1,2,5,5,6,7,7,7-decafluoro-2,6-bis(trifluoromethyl)hept-3-ene F3i4sE (CF₃)₂CFCH═CH—CF(CF₃)C₂F₅1,1,1,2,5,6,6,7,7,7-decafluoro-2,5- bis(trifluoromethyl)hept-3-eneF3i4tE (CF₃)₂CFCH═CH—C(CF₃)₃1,1,1,2,6,6,6-heptafluoro-2,5,5-tris(trifluoromethyl)hex-3- ene F26EC₂F₅CH═CH(CF₂)₅CF₃ 1,1,1,2,2,5,5,6,6,7,7,8,8,9,9,10,10,10-octadecafluorodec-3-ene F26sE C₂F₅CH═CHCF(CF₃)(CF₂)₂C₂F₅1,1,1,2,2,5,6,6,7,7,8,8,9,9,9-pentadecafluoro-5-(trifluoromethyl)non-3-ene F26tE C₂F₅CH═CHC(CF₃)₂CF₂C₂F₅1,1,1,2,2,6,6,7,7,8,8,8-dodecafluoro-5,5- bis(trifluoromethyl)oct-3-eneF35E C₂F₅CF₂CH═CH—(CF₂)₄CF₃ 1,1,1,2,2,3,3,6,6,7,7,8,8,9,9,10,10,10-octadecafluorodec-4-ene F35iE C₂F₅CF₂CH═CH—CF₂CF₂CF(CF₃)₂1,1,1,2,2,3,3,6,6,7,7,8,9,9,9-pentadecafluoro-8-(trifluoromethyl)non-4-ene F35tE C₂F₅CF₂CH═CH—C(CF₃)₂C₂F₅1,1,1,2,2,3,3,7,7,8,8,8-dodecafluoro-6,6- bis(trifluoromethyl)oct-4-eneF3i5E (CF₃)₂CFCH═CH—(CF₂)₄CF₃1,1,1,2,5,5,6,6,7,7,8,8,9,9,9-pentadecafluoro-2-(trifluoromethyl)non-3-ene F3i5iE (CF₃)₂CFCH═CH—CF₂CF₂CF(CF₃)₂1,1,1,2,5,5,6,6,7,8,8,8-dodecafluoro-2,7- bis(trifluoromethyl)oct-3-eneF3i5tE (CF₃)₂CFCH═CH—C(CF₃)₂C₂F₅ 1,1,1,2,6,6,7,7,7-nonafluoro-2,5,5-tris(trifluoromethyl)hept-3-ene F44E CF₃(CF₂)₃CH═CH—(CF₂)₃CF₃1,1,1,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10- octadecafluorodec-5-ene F44iECF₃(CF₂)₃CH═CH—CF₂CF(CF₃)₂1,1,1,2,3,3,6,6,7,7,8,8,9,9,9-pentadecafluoro-2-(trifluoromethyl)non-4-ene F44sE CF₃(CF₂)₃CH═CH—CF(CF₃)C₂F₅1,1,1,2,2,3,6,6,7,7,8,8,9,9,9-pentadecafluoro-3-(trifluoromethyl)non-4-ene F44tE CF₃(CF₂)₃CH═CH—C(CF₃)₃1,1,1,5,5,6,6,7,7,8,8,8-dodecafluoro-2,2,- bis(trifluoromethyl)oct-3-eneF4i4iE (CF₃)₂CFCF₂CH═CH—CF₂CF(CF₃)₂1,1,1,2,3,3,6,6,7,8,8,8-dodecafluoro-2,7- bis(trifluoromethyl)oct-4-eneF4i4sE (CF₃)₂CFCF₂CH═CH—CF(CF₃)C₂F₅1,1,1,2,3,3,6,7,7,8,8,8-dodecafluoro-2,6- bis(trifluoromethyl)oct-4-eneF4i4tE (CF₃)₂CFCF₂CH═CH—C(CF₃)₃ 1,1,1,5,5,6,7,7,7-nonafluoro-2,2,6-tris(trifluoromethyl)hept-3-ene F4s4sE C₂F₅CF(CF₃)CH═CH—CF(CF₃)C₂F₅1,1,1,2,2,3,6,7,7,8,8,8-dodecafluoro-3,6- bis(trifluoromethyl)oct-4-eneF4s4tE C₂F₅CF(CF₃)CH═CH—C(CF₃)₃ 1,1,1,5,6,6,7,7,7-nonafluoro-2,2,5-tris(trifluoromethyl)hept-3-ene F4t4tE (CF₃)₃CCH═CH—C(CF₃)₃1,1,1,6,6,6-hexafluoro-2,2,5,5- tetrakis(trifluoromethyl)hex-3-ene

Compounds of Formula I may be prepared by contacting a perfluoroalkyliodide of the formula R¹I with a perfluoroalkyltrihydroolefin of theformula R²CH═CH₂ to form a trihydroiodoperfluoroalkane of the formulaR¹CH₂CHIR². This trihydroiodoperfluoroalkane can then bedehydroiodinated to form R¹CH═CHR². Alternatively, the olefin R¹CH═CHR²may be prepared by dehydroiodination of a trihydroiodoperfluoroalkane ofthe formula R¹CHICH₂R² formed in turn by reacting a perfluoroalkyliodide of the formula R²¹ with a perfluoroalkyltrihydroolefin of theformula R¹CH═CH₂.

Said contacting of a perfluoroalkyl iodide with aperfluoroalkyltrihydroolefin may take place in batch mode by combiningthe reactants in a suitable reaction vessel capable of operating underthe autogenous pressure of the reactants and products at reactiontemperature. Suitable reaction vessels include fabricated from stainlesssteels, in particular of the austenitic type, and the well-known highnickel alloys such as Monel® nickel-copper alloys, Hastelloy® nickelbased alloys and Inconel® nickel-chromium alloys.

Alternatively, the reaction may take be conducted in semi-batch mode inwhich the perfluoroalkyltrihydroolefin reactant is added to theperfluoroalkyl iodide reactant by means of a suitable addition apparatussuch as a pump at the reaction temperature.

The ratio of perfluoroalkyl iodide to perfluoroalkyltrihydroolefinshould be between about 1:1 to about 4:1, preferably from about 1.5:1 to2.5:1. Ratios less than 1.5:1 tend to result in large amounts of the 2:1adduct as reported by Jeanneaux, et. al. in Journal of FluorineChemistry, Vol. 4, pages 261-270 (1974).

Preferred temperatures for contacting of said perfluoroalkyl iodide withsaid perfluoroalkyltrihydroolefin are preferably within the range ofabout 150° C. to 300° C., preferably from about 170° C. to about 250°C., and most preferably from about 180° C. to about 230° C.

Suitable contact times for the reaction of the perfluoroalkyl iodidewith the perfluoroalkyltrihydroolefin are from about 0.5 hour to 18hours, preferably from about 4 to about 12 hours.

The trihydroiodoperfluoroalkane prepared by reaction of theperfluoroalkyl iodide with the perfluoroalkyltrihydroolefin may be useddirectly in the dehydroiodination step or may preferably be recoveredand purified by distillation prior to the dehydroiodination step.

The dehydroiodination step is carried out by contacting thetrihydroiodoperfluoroalkane with a basic substance. Suitable basicsubstances include alkali metal hydroxides (e.g., sodium hydroxide orpotassium hydroxide), alkali metal oxide (for example, sodium oxide),alkaline earth metal hydroxides (e.g., calcium hydroxide), alkalineearth metal oxides (e.g., calcium oxide), alkali metal alkoxides (e.g.,sodium methoxide or sodium ethoxide), aqueous ammonia, sodium amide, ormixtures of basic substances such as soda lime. Preferred basicsubstances are sodium hydroxide and potassium hydroxide.

Said contacting of the trihydroiodoperfluoroalkane with a basicsubstance may take place in the liquid phase preferably in the presenceof a solvent capable of dissolving at least a portion of both reactants.Solvents suitable for the dehydroiodination step include one or morepolar organic solvents such as alcohols (e.g., methanol, ethanol,n-propanol, isopropanol, n-butanol, isobutanol, and tertiary butanol),nitriles (e.g., acetonitrile, propionitrile, butyronitrile,benzonitrile, or adiponitrile), dimethyl sulfoxide,N,N-dimethylformamide, N,N-dimethylacetamide, or sulfolane. The choiceof solvent may depend on the boiling point product and the ease ofseparation of traces of the solvent from the product duringpurification. Typically, ethanol or isopropanol are good solvents forthe reaction.

Typically, the dehydroiodination reaction may be carried out by additionof one of the reactants (either the basic substance or thetrihydroiodoperfluoroalkane) to the other reactant in a suitablereaction vessel. Said reaction may be fabricated from glass, ceramic, ormetal and is preferably agitated with an impeller or stirring mechanism.

Temperatures suitable for the dehydroiodination reaction are from about10° C. to about 100° C., preferably from about 20° C. to about 70° C.The dehydroiodination reaction may be carried out at ambient pressure orat reduced or elevated pressure. Of note are dehydroiodination reactionsin which the compound of Formula I is distilled out of the reactionvessel as it is formed.

Alternatively, the dehydroiodination reaction may be conducted bycontacting an aqueous solution of said basic substance with a solutionof the trihydroiodoperfluoroalkane in one or more organic solvents oflower polarity such as an alkane (e.g., hexane, heptane, or octane),aromatic hydrocarbon (e.g., toluene), halogenated hydrocarbon (e.g.,methylene chloride, chloroform, carbon tetrachloride, orperchloroethylene), or ether (e.g., diethyl ether, methyl tert-butylether, tetrahydrofuran, 2-methyl tetrahydrofuran, dioxane,dimethoxyethane, diglyme, or tetraglyme) in the presence of a phasetransfer catalyst. Suitable phase transfer catalysts include quaternaryammonium halides (e.g., tetrabutylammonium bromide, tetrabutylammoniumhydrosulfate, triethylbenzylammonium chloride, dodecyltrimethylammoniumchloride, and tricaprylylmethylammonium chloride), quaternaryphosphonium halides (e.g., triphenylmethylphosphonium bromide andtetraphenylphosphonium chloride), or cyclic polyether compounds known inthe art as crown ethers (e.g., 18-crown-6 and 15-crown-5).

Alternatively, the dehydroiodination reaction may be conducted in theabsence of solvent by adding the trihydroiodoperfluoroalkane to a solidor liquid basic substance.

Suitable reaction times for the dehydroiodination reactions are fromabout 15 minutes to about six hours or more depending on the solubilityof the reactants. Typically the dehydroiodination reaction is rapid andrequires about 30 minutes to about three hours for completion. Thecompound of formula I may be recovered from the dehydroiodinationreaction mixture by phase separation after addition of water, bydistillation, or by a combination thereof.

In another embodiment of the present invention, fluoroolefins comprisecyclic unsaturated fluorocarbons (cyclo-[CX═CY(CZW)_(n)-] (Formula II),wherein X, Y, Z, and W are independently selected from H and F, and n isan integer from 2 to 5). In one embodiment the fluoroolefins of FormulaII, have at least about 3 carbon atoms in the molecule. In anotherembodiment, the fluoroolefins of Formula II have at least about 4 carbonatoms in the molecule. In yet another embodiment, the fluoroolefins ofFormula II have at least about 5 carbon atoms in the molecule.Representative cyclic fluoroolefins of Formula II are listed in Table 2.

TABLE 2 Cyclic unsaturated fluorocarbons Structure Chemical nameFC-C1316cc cyclo-CF₂CF₂CF═CF— 1,2,3,3,4,4-hexafluorocyclobuteneHFC-C1334cc cyclo-CF₂CF₂CH═CH— 3,3,4,4-tetrafluorocyclobutene HFC-C1436cyclo-CF₂CF₂CF₂CH═CH— 3,3,4,4,5,5,-hexafluorocyclopentene FC-C1418ycyclo-CF₂CF═CFCF₂CF₂— 1,2,3,3,4,4,5,5-octafluorocyclopentene FC-C151-10ycyclo-CF₂CF═CFCF₂CF₂CF₂— 1,2,3,3,4,4,5,5,6,6- decafluorocyclohexene

The compositions of the present invention may comprise a single compoundof Formula I or formula II, for example, one of the compounds in Table 1or Table 2, or may comprise a combination of compounds of Formula I orFormula II.

In another embodiment, fluoroolefins may comprise those compounds listedin Table 3.

TABLE 3 Name Structure Chemical name HFC-1114 (TFE) CF₂═CF₂tetrafluoroethylene HFC-1216 (HFP) CF₃CF═CF₂ hexafluoropropeneHFC-1225ye CF₃CF═CHF 1,2,3,3,3-pentafluoro-1-propene HFC-1225zcCF₃CH═CF₂ 1,1,3,3,3-pentafluoro-1-propene HFC-1225yc CHF₂CF═CF₂1,1,2,3,3-pentafluoro-1-propene HFC-1234ye CHF₂CF═CHF1,2,3,3-tetrafluoro-1-propene HFC-1234yf CF₃CF═CH₂2,3,3,3-tetrafluoro-1-propene HFC-1234ze CF₃CH═CHF1,3,3,3-tetrafluoro-1-propene HFC-1234yc CH₂FCF═CF₂1,1,2,3-tetrafluoro-1-propene HFC-1234zc CHF₂CH═CF₂1,1,3,3-tetrafluoro-1-propene HFC-1243yf CHF₂CF═CH₂2,3,3-trifluoro-1-propene HFC-1243zf CF₃CH═CH₂ 3,3,3-trifluoro-1-propeneHFC-1243yc CH₃CF═CF₂ 1,1,2-trifluoro-1-propene HFC-1243zc CH₂FCH═CF₂1,1,3-trifluoro-1-propene HFC-1243ye CH₂FCF═CHF1,2,3-trifluoro-1-propene HFC-1243ze CHF₂CH═CHF1,3,3-trifluoro-1-propene FC-1318my CF₃CF═CFCF₃1,1,1,2,3,4,4,4-octafluoro-2-butene FC-1318cy CF₃CF₂CF═CF₂1,1,2,3,3,4,4,4-octafluoro-1-butene HFC-1327my CF₃CF═CHCF₃1,1,1,2,4,4,4-heptafluoro-2-butene HFC-1327ye CHF═CFCF₂CF₃1,2,3,3,4,4,4-heptafluoro-1-butene HFC-1327py CHF₂CF═CFCF₃1,1,1,2,3,4,4-heptafluoro-2-butene HFC-1327et (CF₃)₂C═CHF1,3,3,3-tetrafluoro-2-(trifluoromethyl)-1- propene HFC-1327czCF₂═CHCF₂CF₃ 1,1,3,3,4,4,4-heptafluoro-1-butene HFC-1327cye CF₂═CFCHFCF₃1,1,2,3,4,4,4-heptafluoro-1-butene HFC-1327cyc CF₂═CFCF₂CHF₂1,1,2,3,3,4,4-heptafluoro-1-butene HFC-1336yf CF₃CF₂CF═CH₂2,3,3,4,4,4-hexafluoro-1-butene HFC-1336ze CHF═CHCF₂CF₃1,3,3,4,4,4-hexafluoro-1-butene HFC-1336eye CHF═CFCHFCF₃1,2,3,4,4,4-hexafluoro-1-butene HFC-1336eyc CHF═CFCF₂CHF₂1,2,3,3,4,4-hexafluoro-1-butene HFC-1336pyy CHF₂CF═CFCHF₂1,1,2,3,4,4-hexafluoro-2-butene HFC-1336qy CH₂FCF═CFCF₃1,1,1,2,3,4-hexafluoro-2-butene HFC-1336pz CHF₂CH═CFCF₃1,1,1,2,4,4-hexafluoro-2-butene HFC-1336mzy CF₃CH═CFCHF₂1,1,1,3,4,4-hexafluoro-2-butene HFC-1336qc CF₂═CFCF₂CH₂F1,1,2,3,3,4-hexafluoro-1-butene HFC-1336pe CF₂═CFCHFCHF₂1,1,2,3,4,4-hexafluoro-1-butene HFC-1336ft CH₂═C(CF₃)₂3,3,3-trifluoro-2-(trifluoromethyl)-1- propene HFC-1345qz CH₂FCH═CFCF₃1,1,1,2,4-pentafluoro-2-butene HFC-1345mzy CF₃CH═CFCH₂F1,1,1,3,4-pentafluoro-2-butene HFC-1345fz CF₃CF₂CH═CH₂3,3,4,4,4-pentafluoro-1-butene HFC-1345mzz CHF₂CH═CHCF₃1,1,1,4,4-pentafluoro-2-butene HFC-1345sy CH₃CF═CFCF₃1,1,1,2,3-pentafluoro-2-butene HFC-1345fyc CH₂═CFCF₂CHF₂2,3,3,4,4-pentafluoro-1-butene HFC-1345pyz CHF₂CF═CHCHF₂1,1,2,4,4-pentafluoro-2-butene HFC-1345cyc CH₃CF₂CF═CF₂1,1,2,3,3-pentafluoro-1-butene HFC-1345pyy CH₂FCF═CFCHF₂1,1,2,3,4-pentafluoro-2-butene HFC-1345eyc CH₂FCF₂CF═CF₂1,2,3,3,4-pentafluoro-1-butene HFC-1345ctm CF₂═C(CF₃)(CH₃)1,1,3,3,3-pentafluoro-2-methyl-1-propene HFC-1345ftp CH₂═C(CHF₂)(CF₃)2-(difluoromethyl)-3,3,3-trifluoro-1- propene HFC1345fye CH₂═CFCHFCF₃2,3,4,4,4-pentafluoro-1-butene HFC-1345eyf CHF═CFCH₂CF₃1,2,4,4,4-pentafluoro-1-butene HFC-1345eze CHF═CHCHFCF₃1,3,4,4,4-pentafluoro-1-butene HFC-1345ezc CHF═CHCF₂CHF₂1,3,3,4,4-pentafluoro-1-butene HFC-1345eye CHF═CFCHFCHF₂1,2,3,4,4-pentafluoro-1-butene HFC-1354fzc CH₂═CHCF₂CHF₂3,3,4,4-tetrafluoro-1-butene HFC-1354ctp CF₂═C(CHF₂)(CH₃)1,1,3,3-tetrafluoro-2-methyl-1-propene HFC-1354etm CHF═C(CF₃)(CH₃)1,3,3,3-tetrafluoro-2-methyl-1-propene HFC-1354tfp CH₂═C(CHF₂)₂2-(difluoromethyl)-3,3-difluoro-1-propene HFC-1354my CF₃CF═CHCH₃1,1,1,2-tetrafluoro-2-butene HFC-1354mzy CH₃CF═CHCF₃1,1,1,3-tetrafluoro-2-butene FC-141-10myy CF₃CF═CFCF₂CF₃1,1,1,2,3,4,4,5,5,5-decafluoro-2-pentene FC-141-10cy CF₂═CFCF₂CF₂CF₃1,1,2,3,3,4,4,5,5,5-decafluoro-1-pentene HFC-1429mzt (CF₃)₂C═CHCF₃1,1,1,4,4,4-hexafluoro-2-(trifluoromethyl)- 2-butene HFC-1429myzCF₃CF═CHCF₂CF₃ 1,1,1,2,4,4,5,5,5-nonafluoro-2-pentene HFC-1429mzyCF₃CH═CFCF₂CF₃ 1,1,1,3,4,4,5,5,5-nonafluoro-2-pentene HFC-1429eycCHF═CFCF₂CF₂CF₃ 1,2,3,3,4,4,5,5,5-nonafluoro-1-pentene HFC-1429czcCF₂═CHCF₂CF₂CF₃ 1,1,3,3,4,4,5,5,5-nonafluoro-1-pentene HFC-1429cyccCF₂═CFCF₂CF₂CHF₂ 1,1,2,3,3,4,4,5,5-nonafluoro-1-pentene HFC-1429pyyCHF₂CF═CFCF₂CF₃ 1,1,2,3,4,4,5,5,5-nonafluoro-2-pentene HFC-1429myycCF₃CF═CFCF₂CHF₂ 1,1,1,2,3,4,4,5,5-nonafluoro-2-pentene HFC-1429myyeCF₃CF═CFCHFCF₃ 1,1,1,2,3,4,5,5,5-nonafluoro-2-pentene HFC-1429eyymCHF═CFCF(CF₃)₂ 1,2,3,4,4,4-hexafluoro-3-(trifluoromethyl)- 1-buteneHFC-1429cyzm CF₂═CFCH(CF₃)₂ 1,1,2,4,4,4-hexafluoro-3-(trifluoromethyl)-1-butene HFC-1429mzt CF₃CH═C(CF₃)₂1,1,1,4,4,4-hexafluoro-2-(trifluoromethyl)- 2-butene HFC-1429czymCF₂═CHCF(CF₃)₂ 1,1,3,4,4,4-hexafluoro-3-(trifluoromethyl)- 1-buteneHFC-1438fy CH₂═CFCF₂CF₂CF₃ 2,3,3,4,4,5,5,5-octafluoro-1-penteneHFC-1438eycc CHF═CFCF₂CF₂CHF₂ 1,2,3,3,4,4,5,5-octafluoro-1-penteneHFC-1438ftmc CH₂═C(CF₃)CF₂CF₃ 3,3,4,4,4-pentafluoro-2-(trifluoromethyl)-1-butene HFC-1438czzm CF₂═CHCH(CF₃)₂1,1,4,4,4-pentafluoro-3-(trifluoromethyl)- 1-butene HFC-1438ezymCHF═CHCF(CF₃)₂ 1,3,4,4,4-pentafluoro-3-(trifluoromethyl)- 1-buteneHFC-1438ctmf CF₂═C(CF₃)CH₂CF₃ 1,1,4,4,4-pentafluoro-2-(trifluoromethyl)-1-butene HFC-1447fzy (CF₃)₂CFCH═CH₂3,4,4,4-tetrafluoro-3-(trifluoromethyl)-1- butene HFC-1447fzCF₃CF₂CF₂CH═CH₂ 3,3,4,4,5,5,5-heptafluoro-1-pentene HFC-1447fyccCH₂═CFCF₂CF₂CHF₂ 2,3,3,4,4,5,5-heptafluoro-1-pentene HFC-1447czcfCF₂═CHCF₂CH₂CF₃ 1,1,3,3,5,5,5-heptafluoro-1-pentene HFC-1447mytmCF₃CF═C(CF₃)(CH₃) 1,1,1,2,4,4,4-heptafluoro-3-methyl-2- buteneHFC-1447fyz CH₂═CFCH(CF₃)₂ 2,4,4,4-tetrafluoro-3-(trifluoromethyl)-1-butene HFC-1447ezz CHF═CHCH(CF₃)₂1,4,4,4-tetrafluoro-3-(trifluoromethyl)-1- butene HFC-1447qztCH₂FCH═C(CF₃)₂ 1,4,4,4-tetrafluoro-2-(trifluoromethyl)-2- buteneHFC-1447syt CH₃CF═C(CF₃)₂ 2,4,4,4-tetrafluoro-2-(trifluoromethyl)-2-butene HFC-1456szt (CF₃)₂C═CHCH₃3-(trifluoromethyl)-4,4,4-trifluoro-2-butene HFC-1456szy CF₃CF₂CF═CHCH₃3,4,4,5,5,5-hexafluoro-2-pentene HFC-1456mstz CF₃C(CH₃)═CHCF₃1,1,1,4,4,4-hexafluoro-2-methyl-2-butene HFC-1456fzce CH₂═CHCF₂CHFCF₃3,3,4,5,5,5-hexafluoro-1-pentene HFC-1456ftmf CH₂═C(CF₃)CH₂CF₃4,4,4-trifluoro-2-(trifluoromethyl)-1-butene FC-151-12c CF₃(CF₂)₃CF═CF₂1,1,2,3,3,4,4,5,5,6,6,6-dodecafluoro-1- hexene (or perfluoro-1-hexene)FC-151-12mcy CF₃CF₂CF═CFCF₂CF₃ 1,1,1,2,2,3,4,5,5,6,6,6-dodecafluoro-3-hexene (or perfluoro-3-hexene) FC-151-12mmtt (CF₃)₂C═C(CF₃)₂1,1,1,4,4,4-hexafluoro-2,3- bis(trifluoromethyl)-2-butene FC-151-12mmzz(CF₃)₂CFCF═CFCF₃ 1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene HFC-152- (CF₃)₂C═CHC₂F₅1,1,1,4,4,5,5,5-octafluoro-2- 11mmtz (trifluoromethyl)-2-penteneHFC-152- (CF₃)₂CFCF═CHCF₃ 1,1,1,3,4,5,5,5-octafluoro-4- 11mmyyz(trifluoromethyl)-2-pentene PFBE CF₃CF₂CF₂CF₂CH═CH₂3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene (or (or HFC-1549fz)perfluorobutylethylene) HFC-1549fztmm CH₂═CHC(CF₃)₃4,4,4-trifluoro-3,3-bis(trifluoromethyl)-1- butene HFC-1549mmtts(CF₃)₂C═C(CH₃)(CF₃) 1,1,1,4,4,4-hexafluoro-3-methyl-2-(trifluoromethyl)-2-butene HFC-1549fycz CH₂═CFCF₂CH(CF₃)₂2,3,3,5,5,5-hexafluoro-4-(trifluoromethyl)- 1-pentene HFC-1549mytsCF₃CF═C(CH₃)CF₂CF₃ 1,1,1,2,4,4,5,5,5-nonafluoro-3-methyl-2- penteneHFC-1549mzzz CF₃CH═CHCH(CF₃)₂1,1,1,5,5,5-hexafluoro-4-(trifluoromethyl)- 2-pentene HFC-1558szyCF₃CF₂CF₂CF═CHCH₃ 3,4,4,5,5,6,6,6-octafluoro-2-hexene HFC-1558fzcccCH₂═CHCF₂CF₂CF₂CHF₂ 3,3,4,4,5,5,6,6-octafluoro-2-hexene HFC-1558mmtzc(CF₃)₂C═CHCF₂CH₃ 1,1,1,4,4-pentafluoro-2-(trifluoromethyl)- 2-penteneHFC-1558ftmf CH₂═C(CF₃)CH₂C₂F₅4,4,5,5,5-pentafluoro-2-(trifluoromethyl)- 1-pentene HFC-1567ftsCF₃CF₂CF₂C(CH₃)═CH₂ 3,3,4,4,5,5,5-heptafluoro-2-methyl-1- penteneHFC-1567szz CF₃CF₂CF₂CH═CHCH₃ 4,4,5,5,6,6,6-heptafluoro-2-hexeneHFC-1567fzfc CH₂═CHCH₂CF₂C₂F₅ 4,4,5,5,6,6,6-heptafluoro-1-hexeneHFC-1567sfyy CF₃CF₂CF═CFC₂H₅ 1,1,1,2,2,3,4-heptafluoro-3-hexeneHFC-1567fzfy CH₂═CHCH₂CF(CF₃)₂4,5,5,5-tetrafluoro-4-(trifluoromethyl)-1- pentene HFC-CF₃CF═CHCH(CF₃)(CH₃) 1,1,1,2,5,5,5-heptafluoro-4-methyl-2- 1567myzzmpentene HFC-1567mmtyf (CF₃)₂C═CFC₂H₅1,1,1,3-tetrafluoro-2-(trifluoromethyl)-2- pentene FC-161-14myyCF₃CF═CFCF₂CF₂C₂F₅ 1,1,1,2,3,4,4,5,5,6,6,7,7,7-tetradecafluoro-2-heptene FC-161-14mcyy CF₃CF₂CF═CFCF₂C₂F₅1,1,1,2,2,3,4,5,5,6,6,7,7,7- tetradecafluoro-2-heptene HFC-162-13mzyCF₃CH═CFCF₂CF₂C₂F₅ 1,1,1,3,4,4,5,5,6,6,7,7,7-tridecafluoro-2- hepteneHFC162-13myz CF₃CF═CHCF₂CF₂C₂F₅1,1,1,2,4,4,5,5,6,6,7,7,7-tridecafluoro-2- heptene HFC-162-CF₃CF₂CH═CFCF₂C₂F₅ 1,1,1,2,2,4,5,5,6,6,7,7,7-tridecafluoro-3- 13mczyheptene HFC-162- CF₃CF₂CF═CHCF₂C₂F₅1,1,1,2,2,3,5,5,6,6,7,7,7-tridecafluoro-3- 13mcyz heptene

The compounds listed in Table 2 and Table 3 are available commerciallyor may be prepared by processes known in the art or as described herein.

1,1,1,4,4-pentafluoro-2-butene may be prepared from1,1,1,2,4,4-hexafluorobutane (CHF₂CH₂CHFCF₃) by dehydrofluorination oversolid KOH in the vapor phase at room temperature. The synthesis of1,1,1,2,4,4-hexafluorobutane is described in U.S. Pat. No. 6,066,768,incorporated herein by reference.

1,1,1,4,4,4-hexafluoro-2-butene may be prepared from1,1,1,4,4,4-hexafluoro-2-iodobutane (CF₃CHICH₂CF₃) by reaction with KOHusing a phase transfer catalyst at about 60° C. The synthesis of1,1,1,4,4,4-hexafluoro-2-iodobutane may be carried out by reaction ofperfluoromethyl iodide (CF₃I) and 3,3,3-trifluoropropene (CF₃CH═CH₂) atabout 200° C. under autogenous pressure for about 8 hours.

3,4,4,5,5,5-hexafluoro-2-pentene may be prepared by dehydrofluorinationof 1,1,1,2,2,3,3-heptafluoropentane (CF₃CF₂CF₂CH₂CH₃) using solid KOH orover a carbon catalyst at 200-300° C. 1,1,1,2,2,3,3-heptafluoropentanemay be prepared by hydrogenation of 3,3,4,4,5,5,5-heptafluoro-1-pentene(CF₃CF₂CF₂CH═CH₂).

1,1,1,2,3,4-hexafluoro-2-butene may be prepared by dehydrofluorinationof 1,1,1,2,3,3,4-heptafluorobutane (CH₂FCF₂CHFCF₃) using solid KOH.

1,1,1,2,4,4-hexafluoro-2-butene may be prepared by dehydrofluorinationof 1,1,1,2,2,4,4-heptafluorobutane (CHF₂CH₂CF₂CF₃) using solid KOH.

1,1,1,3,4,4-hexafluoro2-butene may be prepared by dehydrofluorination of1,1,1,3,3,4,4-heptafluorobutane (CF₃CH₂CF₂CHF₂) using solid KOH.

1,1,1,2,4-pentafluoro-2-butene may be prepared by dehydrofluorination of1,1,1,2,2,3-hexafluorobutane (CH₂FCH₂CF₂CF₃) using solid KOH.

1,1,1,3,4-pentafluoro-2-butene may be prepared by dehydrofluorination of1,1,1,3,3,4-hexafluorobutane (CF₃CH₂CF₂CH₂F) using solid KOH.

1,1,1,3-tetrafluoro-2-butene may be prepared by reacting1,1,1,3,3-pentafluorobutane (CF₃CH₂CF₂CH₃) with aqueous KOH at 120° C.

1,1,1,4,4,5,5,5-octafluoro-2-pentene may be prepared from(CF₃CHICH₂CF₂CF₃) by reaction with KOH using a phase transfer catalystat about 60° C. The synthesis of4-iodo-1,1,1,2,2,5,5,5-octafluoropentane may be carried out by reactionof perfluoroethyliodide (CF₃CF₂₁) and 3,3,3-trifluoropropene at about200° C. under autogenous pressure for about 8 hours.

1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene may be prepared from1,1,1,2,2,5,5,6,6,6-decafluoro-3-iodohexane (CF₃CF₂CHICH₂CF₂CF₃) byreaction with KOH using a phase transfer catalyst at about 60° C. Thesynthesis of 1,1,1,2,2,5,5,6,6,6-decafluoro-3-iodohexane may be carriedout by reaction of perfluoroethyliodide (CF₃CF₂I) and3,3,4,4,4-pentafluoro-1-butene (CF₃CF₂CH═CH₂) at about 200° C. underautogenous pressure for about 8 hours.

1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene may be preparedby the dehydrofluorination of1,1,1,2,5,5,5-heptafluoro-4-iodo-2-(trifluoromethyl)-pentane(CF₃CHICH₂CF(CF₃)₂) with KOH in isopropanol. CF₃CHICH₂CF(CF₃)₂ is madefrom reaction of (CF₃)₂CFI with CF₃CH═CH₂ at high temperature, such asabout 200° C.

1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene may be prepared by the reactionof 1,1,1,4,4,4-hexafluoro-2-butene (CF₃CH═CHCF₃) withtetrafluoroethylene (CF₂═CF₂) and antimony pentafluoride (SbF₅).

2,3,3,4,4-pentafluoro-1-butene may be prepared by dehydrofluorination of1,1,2,2,3,3-hexafluorobutane over fluorided alumina at elevatedtemperature.

2,3,3,4,4,5,5,5-ocatafluoro-1-pentene may be prepared bydehydrofluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentane over solidKOH.

1,2,3,3,4,4,5,5-octafluoro-1-pentene may be prepared bydehydrofluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentane overfluorided alumina at elevated temperature.

Many of the compounds of Formula I, Formula II, Table 1, Table 2, andTable 3 exist as different configurational isomers or stereoisomers.When the specific isomer is not designated, the present invention isintended to include all single configurational isomers, singlestereoisomers, or any combination thereof. For instance, F11E is meantto represent the E-isomer, Z-isomer, or any combination or mixture ofboth isomers in any ratio. As another example, HFC-1225ye is meant torepresent the E-isomer, Z-isomer, or any combination or mixture of bothisomers in any ratio.

The term “entrainer” is used herein to describe any compound that wouldbe effective in separation of fluoroolefins from mixtures comprising HFand fluoroolefin in an azeotropic distillation process. Included asuseful entrainers are those compounds that form azeotropes with one ormore of the components of a mixture, including fluoroolefins, HF, andpossible hydrofluorocarbons for which the boiling point of at least oneof such azeotropes is lower than the boiling point of thefluoroolefin/HF azeotrope.

Entrainers may be selected from the group consisting of hydrocarbons,chlorocarbons, chlorofluorocarbons, hydrochlorofluorocarbons,hydrofluorocarbons, perfluorocarbons, fluoroethers, HFPO, SF₆, chlorine,hexafluoroacetone, and mixtures thereof.

Hydrocarbon entrainers comprise compounds containing 1 to 5 carbon atomsand hydrogen. Hydrocarbon entrainers may be linear, branched, cyclic,saturated or unsaturated compounds. Representative hydrocarbonentrainers include but are not limited to methane, ethane, ethylene,acetylene, vinylacetylene, n-propane, propylene, propyne, cyclopropane,cyclopropene, propadiene, n-butane, isobutane, 1-butene, isobutene,1,3-butadiene, 2,2-dimethylpropane, cis-2-butene, trans-2-butene,1-butyne, n-pentane, isopentane, neopentane, cyclopentane, 1-pentene,2-pentene, and mixtures thereof.

Chlorocarbon entrainers comprise compounds containing carbon, chlorineand optionally hydrogen, including but not limited to methylene chloride(CH₂Cl₂), and methyl chloride (CH₃Cl).

Chlorofluorocarbon (CFC) entrainers comprise compounds with carbon,chlorine and fluorine. Representative CFCs include but are not limitedto dichlorodifluoromethane (CFC-12), 2-chloro-1,1,2-trifluoroethylene,chloropentafluoroethane (CFC-115),1,2-dichloro-1,1,2,2-tetrafluoroethane (CFC-114),1,1-dichloro-1,2,2,2-tetrafluoroethane (CFC-114a),1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113),1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113a),1,1,2-trichloro-1,2,3,3,3-pentafluoropropane (CFC-215bb),2,2-dichloro-1,1,1,3,3,3-hexafluoropropane (CFC-216aa),1,2-dichloro-1,1,2,3,3,3-hexafluoropropane (CFC-216ba),2-chloro-1,1,1,2,3,3,3-heptafluoropropane (CFC-217ba),2-chloro-1,1,3,3,3-pentafluoropropene (CFC-1215xc), and mixturesthereof.

Hydrochlorofluorocarbon (HCFC) entrainers comprise compounds withcarbon, chlorine, fluorine and hydrogen. Representative HCFCs includebut are not limited to dichlorofluoromethane (HCFC-21),1,1-dichloro-3,3,3-trifluoroethane (HCFC-123),1,1-dichloro-1-fluoroethane (HCFC-141b),2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124),1-chloro-1,1,2,2-tetrafluoroethane (HCFC-124a),2-chloro-1,1,1-trifluoroethane (HCFC-133a), 1-chloro-1,1-difluoroethane(HCFC-142b), 2-chloro-1,1-difluoroethylene (HCFC-1122), and mixturesthereof.

Hydrofluorocarbon (HFC) entrainers comprise compounds that containcarbon, hydrogen and fluorine. Representative HFCs include but are notlimited to 1,1,2-trifluoroethylene (HFC-1123), 1,1-difluoroethylene(HFC-1132a), 1,2,3,3,3-pentafluoropropene (HFC-1225ye, either of the Z-or E-isomers or a mixture thereof), 2,3,3,3-tetrafluoropropene(HFC-1234yf), 3,3,3-trifluoropropene (HFC-1243zf),1,3,3,3-tetrafluoropropene (HFC-1234ze, either of the Z- or E-isomers ora mixture thereof), 1,1,1,3,4,4,5,5,5-nonafluoro-2-pentene(HFC-1429mzy), 1,1,1,2,2,4,5,5,6,6,7,7,7-tridecafluoro-3-heptene(HFC-162-13mczy), 1,1,1,2,2,3,5,5,6,6,7,7,7-tridecafluoro-3-heptene(HFC-162-13mcyz), and mixtures thereof.

Perfluorocarbon (PFC) entrainers comprise compounds with carbon andfluorine only. Representative PFCs include but are not limited tohexafluoroethane (PFC-116), octafluoropropane (PFC-218),1,1,1,4,4,4-hexafluoro-2-butyne (PFBY-2), hexafluoropropylene (HFP,PFC-1216), hexafluorocyclopropane (PFC-C216), octafluorocyclobutane(PFC-C318), decafluorobutane (PFC-31-10, any isomer(s)),2,3-dichloro-1,1,1,4,4,4-hexafluoro-2-butene (PFC-1316mxx),octafluoro-2-butene (PFC-1318my, cis and trans), hexafluorobutadiene(PFC-2316), and mixtures thereof.

Fluoroether entrainers comprise compounds with carbon, fluorine,optionally hydrogen and at least one ether group oxygen. Representativefluoroethers include but are not limited totrifluoromethyl-difluoromethyl ether (CF₃OCHF₂, HFOC-125E),1,1-difluorodimethyl ether, tetrafluorodimethylether (HFOC-134E),difluoromethyl methyl ether (CHF₂OCH₃, HFOC-152aE), pentafluoroethylmethyl ether, and mixtures thereof.

Miscellaneous other compounds that may be useful as entrainers includeHFPO, chlorine (Cl₂), hexafluoroacetone, PMVE(perfluoromethylvinylether), PEVE (perfluoroethylvinylether), andmixtures thereof.

Entrainers as described above are available commercially or may beproduced by methods known in the art.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of embodiments of the present invention, suitablemethods and materials are described below. All publications, patentapplications, patents, and other references mentioned herein areincorporated by reference in their entirety, unless a particular passageis cited. In case of conflict, the present specification, includingdefinitions, will control. In addition, the materials, methods, andexamples are illustrative only and not intended to be limiting.

2. Separation Process—Azeotropic Distillation with No Entrainer

It has been discovered that some fluoroolefins form azeotropecompositions with HF. Generally, the fluoroolefin/HF azeotropecomposition will boil at a lower temperature than either of thecorresponding pure compounds. Several examples of such fluoroolefin/HFazeotropes are disclosed in U.S. Patent Publication numbers 2007-0100173A1, 2007-0100174 A1, 2007-0099811 A1, 2007-0100175 A1, 2007-0100176 A1,and 2006-0116538 A1.

It has been unexpectedly calculated that in a few cases azeotropecompositions comprising fluoroolefins and HF may form two liquid phaseswhen condensed and/or cooled. The two phases comprise afluoroolefin-rich phase and an HF-rich phase. This phase behavior allowsunique separation schemes utilizing liquid-liquid separation (such asdecantation) of the two phases that are not possible with many saturatedhydrofluorocarbons, which in general do not phase separate in the samemanner.

In one embodiment, the present disclosure provides a process forseparating a mixture comprising HF and fluoroolefin, said processcomprising a) feeding the composition comprising HF and fluoroolefin toa first distillation column; b) removing an azeotrope compositioncomprising HF and fluoroolefin as a first distillate and either i) HF orii) fluoroolefin as a first column bottoms composition; c) condensingthe first distillate to form two liquid phases, being i) an HF-richphase and ii) a fluoroolefin-rich phase; and d) recycling a first liquidphase enriched in the same compound that is removed as the first columnbottoms, said first liquid phase being either i) HF-rich phase or ii)fluoroolefin-rich phase, back to the first distillation column.

Additionally, in another embodiment, the process as described in theparagraph above may further comprise feeding a second liquid phase notrecycled in step (d), said second liquid phase being either i) HF-richphase or ii) fluoroolefin-rich phase, to a second distillation zone, andrecovering the compound not recovered in step (b) as the first columnbottoms composition as the second column bottoms composition.

In another embodiment, a process is provided for separating afluoroolefin from a mixture comprising hydrogen fluoride and saidfluoroolefin, wherein said fluoroolefin is present in a concentrationgreater than the azeotrope concentration for hydrogen fluoride and saidfluoroolefin, said process comprising: a) feeding said mixturecomprising hydrogen fluoride and said fluoroolefin to a firstdistillation column; b) removing an azeotrope composition comprisinghydrogen fluoride and fluoroolefin as a first distillate from the firstdistillation column; c) recovering fluoroolefin essentially free ofhydrogen fluoride as a first bottoms composition from the firstdistillation column; and d) condensing the first distillate to form twoliquid phases, being i) a hydrogen fluoride-rich phase and ii) afluoroolefin-rich phase; and e) recycling the fluoroolefin-rich phase tothe first distillation column.

In another embodiment, the process may further comprise: a) feeding thehydrogen fluoride-rich phase to a second distillation column, and b)recovering hydrogen fluoride essentially free of fluoroolefin from thebottom of the second distillation column.

In another embodiment, the second distillate comprising HF andfluoroolefin may be recycled to the two liquid phases.

In one embodiment, wherein the composition comprising HF andfluoroolefin has a concentration of fluoroolefin that is greater thanthe azeotrope concentration for fluoroolefin and HF, the firstdistillation column removes the excess fluoroolefin from the bottom ofthe column and the azeotrope composition exits the top of the column asthe distillate. In another embodiment, the azeotrope compositioncomprising HF and fluoroolefin may be condensed and cooled therebyforming two liquid phases, an HF-rich phase and a fluoroolefin-richphase.

In one embodiment, the fluoroolefin-rich phase is recycled back to thefirst distillation column and the HF-rich phase is fed to a seconddistillation column. As the HF-rich phase may have HF in excess of theazeotrope composition for HF/fluoroolefin, the excess HF will be removedfrom the second distillation column bottom.

Referring now to FIG. 1, one embodiment of this process is illustrated.A composition comprising HF and fluoroolefin is fed to a first column110 via stream 100. This first column is operated under appropriateconditions to approach the low-boiling HF/fluoroolefin azeotrope.Because fluoroolefin is being fed to this first column in excess of thatneeded to form the azeotrope with the HF, fluoroolefin is recovered asthe bottoms of the column via stream 120, while a composition near tothe HF/fluoroolefin azeotrope is recovered as distillate via stream 130.Stream 130 is condensed in 140, mixed with a nearly azeotropiccomposition recycled from a second column 210 via stream 250 and thecombined stream is sub-cooled in cooler 160 and sent to decanter 180where the combined stream 170 separates into separate fluoroolefin-rich(190) and HF-rich (200) streams. Stream 190 is recycled to the firstcolumn as reflux. Stream 200 is fed to the top stage of the seconddistillation column 210, operated under conditions to approach theHF/fluoroolefin azeotrope. Because the HF is being fed to this secondcolumn in excess of that needed to form the low-boiling HF/fluoroolefinazeotrope, HF is recovered as the bottoms of the column via stream 220while a composition close to the HF/fluoroolefin azeotrope is recoveredas distillate via stream 230. Stream 230 is condensed in 240, mixed withthe nearly azeotropic composition from the first column via stream 150and fed to cooler 160 and then decanter 180.

In another embodiment, a process is provided for separating hydrogenfluoride from a mixture comprising hydrogen fluoride and a fluoroolefin,wherein hydrogen fluoride is present in a concentration greater than theazeotrope concentration for hydrogen fluoride and said fluoroolefin,said process comprising: a) feeding said mixture comprising hydrogenfluoride and fluoroolefin to a first distillation column; b) removing anazeotrope composition comprising fluoroolefin and HF as a firstdistillate from the first distillation column; c) recovering hydrogenfluoride essentially free of fluoroolefin from the bottom of the firstdistillation column d) condensing the first distillate to form twoliquid phases, being an fluoroolefin-rich phase and a hydrogenfluoride-rich phase; and e) recycling the HF-rich phase to the firstdistillation column.

In another embodiment, the process may further comprise: a) feeding thefluoroolefin-rich phase to a second distillation column; and b)recovering fluoroolefin essentially free of hydrogen fluoride from thebottom of the second distillation column.

In another embodiment, the process may further comprise: recycling thehydrogen fluoride-rich phase to the first distillation column.

In another embodiment, the composition comprising HF and fluoroolefinhas a greater concentration of HF than the azeotrope composition for HFand fluoroolefin. The excess HF may be removed from the bottom of thefirst distillation column and the azeotrope composition exits as thedistillate. In another embodiment, the azeotrope composition comprisingHF and fluoroolefin may be condensed and cooled thereby forming twoliquid phases, an HF-rich phase and a fluoroolefin-rich phase. For thisembodiment, the HF-rich phase is recycled back to the first distillationcolumn and the fluoroolefin-rich phase is fed to a second distillationcolumn. As the fluoroolefin-rich phase may have fluoroolefin in excessof the azeotrope composition for HF/fluoroolefin, the excessfluoroolefin may be removed from the second distillation column bottomas fluoroolefin essentially free of HF.

Referring again to FIG. 1, another embodiment of this process isillustrated. A composition comprising HF and fluoroolefin is fed to afirst column 110 via stream 100. This first column is operated underappropriate conditions to approach the low-boiling HF/fluoroolefinazeotrope. Because HF is being fed to this first column in excess ofthat needed to form the azeotrope with the fluoroolefin, HF is recoveredas the bottoms of the column via stream 120, while a composition near tothe HF/fluoroolefin azeotrope is recovered as distillate via stream 130.Stream 130 is condensed in 140, mixed with a nearly azeotropiccomposition recycled from a second column via stream 250 and thecombined stream is sub-cooled in cooler 160 and sent to decanter 180where the combined stream 170 separates into separate HF-rich (190) andfluoroolefin-rich (200) streams. Stream 190 is recycled to the firstcolumn as reflux. Stream 200 is fed to the top stage of the seconddistillation column 210, operated under conditions to approach theHF/fluoroolefin azeotrope. Because fluoroolefin is being fed to thissecond column in excess of that needed to form the low-boilingHF/fluoroolefin azeotrope, Fluoroolefin is recovered as the bottoms ofthe column via stream 220, while a composition close to theHF/fluoroolefin azeotrope is recovered as distillate via stream 230.Stream 230 is condensed in 240, mixed with the nearly azeotropiccomposition from the first column via stream 150 and fed to cooler 160and then decanter 180.

In one embodiment the operating conditions for the first and seconddistillation columns will depend upon the fluoroolefin being purifiedand the relative amounts of HF and fluoroolefin in the composition to beseparated.

In one embodiment, the first and second distillation column may operateat from about 14.7 psia (101 kPa) to about 300 psia (2068 kPa), with atop temperature of from about −50° C. to about 200° C. and a bottomtemperature from about −30° C. to about 220° C. In another embodiment,the pressure will range from about 50 psia (345 kPa) to about 250 psia(1724 kPa), with a top temperature of from about −25° C. to about 100°C. and a bottom temperature from about 0° C. to about 150° C.

3. Separation Process—Azeotropic Distillation with an Entrainer

Azeotropic distillation for separating fluoroolefin from mixtures of HFand fluoroolefin may, in another embodiment, be carried out using anentrainer compound. For the process including an entrainer, theazeotrope composition need not phase separate upon condensing andcooling as described above.

In one embodiment, the entrainer serves to provide an improvedliquid-liquid phase separation for a system wherein that separationwould otherwise not be effective.

In one embodiment, the fluoroolefin is present in the HF/fluoroolefinmixture in a concentration greater than the azeotrope concentration forsaid fluoroolefin and HF. Thus, in one embodiment is provided a processfor the purification of a fluoroolefin from a mixture comprisingfluoroolefin and HF, wherein said fluoroolefin is present in saidmixture in a concentration greater than the azeotrope concentration forsaid fluoroolefin and HF, said process comprising:

a. adding an entrainer to the mixture comprising fluoroolefin and HFthus forming a second mixture;

b. distilling said second mixture in a first distillation step to form afirst distillate composition comprising HF, fluoroolefin, and entrainer,and a first bottoms composition comprising fluoroolefin essentially freeof HF and entrainer;

c. condensing said first distillate composition to form two liquidphases, being i) an HF-rich phase and ii) an entrainer-rich phase; and

d. optionally recycling the entrainer-rich phase back to the firstdistillation step. In another embodiment, the process further comprisesfeeding the HF-rich phase to a second distillation step and forming asecond distillate composition comprising entrainer, fluoroolefin and HFand a bottoms composition comprising HF essentially free of fluoroolefinand entrainer. In another embodiment, the process may further compriserecycling said second distillate composition back to the two liquidphases.

The process for separating a fluoroolefin from a first compositioncomprising HF and fluoroolefin comprises contacting said firstcomposition with an entrainer to form a second composition. Thecontacting may occur in a first distillation column, or the secondcomposition may be formed by mixing the components prior to feeding to adistillation column in a pre-mixing step.

The weight ratio of the HF and fluoroolefin in the first compositionwill depend upon the means of producing the composition. In oneembodiment, the HF may be from about 3 weight percent to about 85 weightpercent of the composition; the fluoroolefin may be from about 97 weightpercent to about 15 weight percent.

In another embodiment, the HF may be from about 5 weight percent toabout 50 weight percent and the fluoroolefin may be from about 95 weightpercent to about 50 weight percent

In yet another embodiment the composition comprising HF and fluoroolefinmay be produced in a dehydrofluorination reactor resulting in a 50/50mole ratio of HF to the fluoroolefin.

In one embodiment, the compositions comprising HF and fluoroolefin maybe prepared by any convenient method to combine the desired amounts ofthe individual components. A preferred method is to weigh the desiredcomponent amounts and thereafter combine the components in anappropriate vessel. Agitation may be used, if desired.

Alternatively, the compositions comprising HF and fluoroolefin may beprepared by feeding the effluent from a reactor, including adehydrofluorination reactor that contains HF and fluoroolefin, to thefirst distillation column. The entrainer may be added at a separate feedpoint such that the second composition is formed directly in thedistillation column. Alternatively, the entrainer may be mixed with thefirst composition comprising HF and fluoroolefin thus forming the secondcomposition prior to the distillation column in a pre-mixing step.

In one embodiment of the separation process, a composition comprisingfluoroolefin and HF is fed directly to a first distillation column. Inanother embodiment, the fluoroolefin and HF may be pre-mixed with anentrainer prior to the distillation column. The pre-mixing step mayoccur in a cooler (160 in FIG. 2). Then the cooled mixture is fed to adecanter (180 in FIG. 2) prior to feeding to the distillation column.

In one embodiment, the first distillate composition comprises a lowboiling azeotrope of HF and entrainer optionally containing minoramounts of fluoroolefin. Further, in another embodiment, thefluoroolefin essentially free of HF and optionally minor amounts ofentrainer may be recovered from the bottom of the first distillationcolumn.

The operating variables for the first distillation column will dependstrongly on the entrainer being used in the separation process. Ingeneral the first distillation column may operate at pressures fromabout 14.7 psia (101 kPa) to about 500 psia (3448 kPa) with a toptemperature of from about −50° C. to about 100° C. and a bottomtemperature of from about −30° C. to about 200° C. In anotherembodiment, the first distillation column will operate at pressures fromabout 100 psia (690 kPa) to about 400 psia (2758 kPa) with a toptemperature of from about −50° C. to about 50° C. and a bottomtemperature from about 10° C. to about 150° C.

It was surprisingly calculated that in some few cases, azeotropes of HFand compounds used as entrainers will separate into HF-rich andentrainer-rich liquid fractions upon condensing and being cooled. In oneembodiment, the first distillate composition may be fed to a liquidseparation zone (e.g. decanter). The first distillate compositioncomprising an azeotrope of HF and entrainer may be phase separatedforming two liquid phases, one being HF-rich and the other beingentrainer-rich. The lower density phase may be recovered from the top ofthe liquid separation zone and the higher density phase may be recoveredfrom the bottom of the liquid separation zone. The entrainer-rich phase(whether higher or lower density) may be fed back to the firstdistillation column. In one embodiment the HF-rich phase may be fed to asecond distillation column or in another embodiment, the HF-rich phasemay be split to send some portion back to the first distillation column(in order to provide more reflux and allow the first distillation columnto operate properly) and the remainder may be fed to the seconddistillation column. The second distillation column allows recovery ofHF essentially free of fluoroolefin and entrainer as a bottomscomposition. The top composition comprising fluoroolefin, HF andentrainer may be recycled to the liquid separation zone, be utilized insome other manner, or disposed. The operating variables for the seconddistillation column will depend strongly on the entrainer being used inthe separation process. In general the second distillation column mayoperate at pressures from about 14.7 psia (101 kPa) to about 500 psia(3448 kPa) with a top temperature of from about −50° C. to about 100° C.and a bottom temperature of from about −30° C. to about 200° C. Inanother embodiment, the first distillation column will operate atpressures from about 100 psia (690 kPa) to about 400 psia (2758 kPa)with a top temperature of from about −25° C. to about 50° C. and abottom temperature from about zero ° C. to about 150° C.

Referring now to FIG. 2, a composition comprising HF and fluoroolefin isfed to a first distillation column 110 via stream 100. An entrainer-richcomposition is also fed to the top stage of column 110 via stream 190.If the combined amount of fluoroolefin in streams 100 and 190 is inexcess of that needed to form the low-boiling HF/fluoroolefin azeotrope,fluoroolefin is recovered essentially free of both HF and entrainer fromthe bottom of column 110 via stream 120. A ternary compositioncomprising HF, fluoroolefin, and entrainer, but enriched in fluoroolefinrelative to stream 190, leaves the top of the first column as the firstdistillate stream 130. Stream 130 is condensed by condenser 140 formingstream 150 and mixed with a condensed second distillate stream 250 froma second distillation column. In one embodiment, additional entrainermay be added via stream 260, if needed. Combined streams 150, 250, and260 are fed to cooler 160 and then to decanter 180 where the sub-cooledliquid stream 170 separates into entrainer-rich and HF-rich liquid phasecompositions which leave the decanter via streams 190 and 200,respectively. The fluoroolefin present distributes between the twoliquid phases with the majority ending up in the entrainer-rich phase.The HF-rich composition stream 200 is fed to the top stage of the seconddistillation column 210. Because the amount of HF in stream 200 is inexcess of that needed to form a low-boiling HF/fluoroolefin azeotrope,HF is recovered as a product stream essentially free of bothfluoroolefin and entrainer from the bottom of column 210 via stream 220.A ternary composition comprising HF, fluoroolefin and entrainer, butenriched in entrainer relative to stream 200, leaves the top of thesecond column as the second distillate stream 230. Stream 230 iscondensed in condenser 240, forming stream 250, and combined withstreams 150 and 260 previously described.

Alternatively, in another embodiment, rather than feed theHF/fluoroolefin mixture directly to the distillation column 110, themixture may be fed to cooler 160 and then to decanter 180 where themixture phase separates. Then stream 190 carries the mixture of HF,fluoroolefin and entrainer to the first distillation column 110.

In another embodiment, the concentration of HF in the HF/fluoroolefinmixture is greater than the concentration in the azeotrope offluoroolefin and HF. Thus, in another embodiment is provided a processfor the purification of HF from a mixture comprising a fluoroolefin andHF, wherein HF is present in a concentration greater than the azeotropeconcentration for HF and said fluoroolefin, said process comprising:

a. adding an entrainer to the mixture comprising fluoroolefin and HFthus forming a second mixture;

b. distilling said second mixture in a first distillation step to form afirst distillate composition comprising HF, entrainer, and afluoroolefin, and a first bottoms composition comprising HF essentiallyfree of fluoroolefin and entrainer;

c. condensing said first distillate composition to form two liquidphases, being i) an entrainer-rich phase and ii) an HF-rich phase; and

d. optionally recycling the HF-rich phase back to the first distillationstep. In another embodiment, the process may further comprising feedingthe HF-rich phase to a second distillation step and forming a seconddistillate composition comprising entrainer, HF, and fluoroolefin, and abottoms composition comprising fluoroolefin essentially free ofentrainer. In another embodiment, the process may further compriserecycling said second distillate composition back to the two liquidphases.

Referring again to FIG. 2, a composition comprising HF and fluoroolefinis fed to a first distillation column 110 via stream 100. An HF-richcomposition is also fed to the top stage of column 110 via stream 190.If the combined amount of HF in streams 100 and 190 is in excess of thatneeded to form the low-boiling HF/fluoroolefin azeotrope, HF isrecovered essentially free of both fluoroolefin and entrainer from thebottom of column 110 via stream 120. A composition near theHF/fluoroolefin azeotrope with a minor amount of entrainer is recoveredas the first distillate via stream 130. Stream 130 is condensed bycondenser 140 forming stream 150 and mixed with a condensed seconddistillate stream 250 from a second distillation column. In oneembodiment, additional entrainer may be added via stream 260, if needed.Combined streams 150, 250, and 260 are fed to cooler 160 and then todecanter 180 where the sub-cooled liquid stream 170 separates intoHF-rich and entrainer-rich liquid phase compositions which leave thedecanter via streams 190 and 200, respectively. The fluoroolefin presentdistributes between the two liquid phases with the majority ending up inthe entrainer-rich phase. The entrainer-rich composition stream 200 isfed to the top stage of the second distillation column 210. Because theamount of fluoroolefin in stream 200 is in excess of that needed to forma low-boiling entrainer/fluoroolefin azeotrope, fluoroolefin isrecovered as a product stream essentially free of both HF and entrainerfrom the bottom of column 210 via stream 220. A ternary compositioncomprising entrainer, fluoroolefin, and HF, but enriched in entrainerrelative to stream 200 leaves the top of the second column as the seconddistillate stream 230. Stream 230 is condensed in condenser 240, formingstream 250, and combined with streams 150 and 260 previously described.

Alternatively, in another embodiment, rather than feed theHF/fluoroolefin mixture directly to the distillation column 110, themixture may be fed to cooler 160 and then to decanter 180 where themixture phase separates. Then stream 190 carries the mixture of HF,fluoroolefin and entrainer as the HF-rich phase to the firstdistillation column 110.

4. Separation of HFC-236 from HFC-1225ye and HF

HFC-1225ye is a valuable fluorocarbon useful as a refrigerant, blowingagent, aerosol propellant, and sterilant among other uses. HFC-1225yeexists as either of two isomers, HFC-Z-1225ye and HFC-E-1225ye.Hereafter, by HFC-1225ye is meant either of the two isomers and/ormixtures of the two isomers.

HFC-1225ye may be produced by dehydrofluorination of certain HFC-236(hexafluoropropane) isomers. By HFC-236 is meant any isomer ofhexafluoropropane and any combinations of any isomers ofhexafluoropropane that can yield HFC-1225ye upon dehydrofluorination.Isomers of hexafluoropropane include HFC-236ea(1,1,1,2,3,3-hexafluoropropane) and HFC-236cb(1,1,1,2,2,3-hexafluoropropane).

HFC-1225ye may be prepared by the vapor phase dehydrofluorination ofHFC-236ea or HFC-236cb by processes known in the art, such as thosedescribed in U.S. Pat. No. 5,396,000, U.S. Pat. No. 5,679,875, U.S. Pat.No. 6,031,141, and U.S. Pat. No. 6,369,284. For example, HFC-1225ye canbe prepared by passing HFC-236ea, HFC-236cb or mixtures of HFC-236ea andHFC-236cb over a chrome oxide catalyst at elevated temperatures, forexample, at above 300 deg C. The product stream from this reactioncontains HFC-1225ye, HF and any unreacted HFC-236ea and/or HFC-236cb.

In one embodiment, a process is provided for the separation ofHFC-1225ye from a mixture of HFC-1225ye, HF, and at least one ofHFC-236ea or HFC-236cb, said process comprising:

a) subjecting said mixture to a first distillation step, whereinadditional HFC-1225ye is fed from a second distillation step, to form afirst distillate comprising an azeotrope of HFC-1225ye and HF and afirst bottoms composition comprising at least one of HFC-236ea orHFC-236cb;

b) feeding said first distillate to a second distillation step to form asecond distillate comprising an azeotrope of HFC-1225ye and HF and asecond bottoms composition comprising HFC-1225ye essentially free of HF;

c) condensing said second distillate to form two liquid phases, being i)an HF-rich phase and ii) an HFC-1225ye-rich phase; and

d) recycling the HFC-1225ye-rich phase from (c) back to the seconddistillation step. In another embodiment, the process may furthercomprise feeding the HF-rich phase to a third distillation step to forma third distillate comprising an azeotrope of HFC-1225ye and HF and athird bottoms composition comprising HF essentially free of HFC-1225ye.

In this embodiment the azeotropic distillation involves providing anexcess of HFC-1225ye to the distillation column in addition to thatproduced from the dehydrofluorination reaction of HFC-236ea and/orHFC-236cb. In this embodiment, HFC-1225ye serves as an entrainer in thedistillation process. If the proper total amount of HFC-1225ye is fed tothe column, then all the HF may be taken overhead as an azeotropecomposition containing HFC-1225ye and HF. Enough HFC-1225ye can beprovided, for example, by feeding supplemental HFC-1225ye to thedistillation column over that exiting in the dehydrofluorinationreaction product stream. Thus, the HFC-236ea and/or HFC-236cb removedfrom the column bottoms may be essentially free of HF.

For example, a reactor product mixture comprising HF, HFC-1225ye andHFC-236ea may be fed to a first distillation column operated underconditions to form the HF/HFC-1225ye azeotrope with the HF/HFC-1225yeazeotrope being removed from the distillation column as the overheaddistillate. The HF in this distillate may then be separated and removedfrom the HFC-1225ye by other means, e.g. by using pressure swingdistillation or the methods as disclosed herein. Some portion of theHFC-1225ye so obtained can be recycled back to the first distillationcolumn in quantities sufficient so that all the HF fed to the firstdistillation column is removed from that column as the HF/HFC-1225yeazeotrope, thus producing a HFC-236ea bottoms stream essentially free ofHF.

Where the composition to be separated is formed by dehydrohalogenatingeither of HFC-236ea or HFC-236cb, it is desirable to recycle anyunreacted HFC-236ea or HFC-236cb back to the reactor so that they may beconverted to HFC-1225ye. However, it is necessary that HF and HFC-1225yebe removed from said unreacted HFC-236ea or HFC-236cb prior to beingrecycled so as not to inhibit the equilibrium reaction. It is alsonecessary that the HF be removed from the HFC-1225ye to allow its use asa refrigerant or in other applications.

Referring now to FIG. 3, a stream comprising HF, HFC-1225ye, and atleast one of HFC-236ea and HFC-236cb is fed to a first distillationcolumn via stream 10, with the column operated under conditions toapproach the low-boiling HF/HFC-1225ye azeotrope, which is removed asdistillate via streams 50, 70, and 90. Enough supplemental HFC-1225ye isrecycled from the second column bottoms to this first column via stream20 to enable all of the HF to be removed from the HFC-236cb and/orHFC-236ea. The HFC-236cb and/or HFC-236ea are obtained essentially freeof HFC-1225ye and HF as the bottoms product from this column via stream40.

The near HF/HFC-1225ye azeotropic composition in stream 50 is condensedand divided into reflux 80 and distillate 90 streams. Distillate stream90 may be fed to a second distillation column 110 via stream 100 asshown and indicated, mixed with distillate streams 150 and 250 from thesecond and third columns, respectively, and sent to cooler 160 anddecanter 180, or be divided between these two destinations. Because ofthe desire to remove all of the HF overhead in column 30, excessHFC-1225ye would be recycled to column 30, making the composition ofstreams 50, 70, 80, 90, and 100 lie on the HFC-1225ye-rich side of theazeotrope. Therefore, if distillate stream 90 is sent via stream 100 toa second distillation column, it should be sent to the column whichproduces purified HFC-1225ye as the bottoms product.

In one embodiment, distillate stream 90 via stream 260 is mixed withdistillate streams 150 and 250 from the second and third columns,respectively, and sent to cooler 160, forming sub-cooled stream 170,which is fed to decanter 180. In the decanter, stream 170 separates intoHFC-1225ye-rich and HF-rich liquid fractions, which are removed asstreams 190 and 200. The HFC-1225ye-rich stream from the decanter is fedvia stream 190 to a second distillation column 110 containing 19theoretical stages and operated under conditions to approach theHFC-1225ye/HF azeotrope, which is distilled overhead as distillatestream 130, condensed in condenser 140, and mixed with the distillatesfrom the first and third columns via stream 150. Column 110 produces abottoms stream of HFC-1225ye essentially free of HF via stream 120. Partof the HFC-1225ye bottoms stream 120 is recycled to the first column viastream 20, as previously described, and the rest becomes the purifiedHFC-1225ye product removed via stream 125. The HF-rich stream from thedecanter is fed via stream 200 to a third distillation column 210operated under conditions to approach the HFC-1225ye/HF azeotrope, whichis distilled overhead as distillate as stream 230 which is condensed incondenser 250 and mixed with the distillates from the first and secondcolumns via stream 250. Column 210 produces a bottoms stream of HFessentially free of HFC-1225ye via stream 220.

In another aspect of this invention, an entrainer may be added to enableseparation of the HF from the HFC-1225ye, or of the HF from theHFC-1225ye and HFC-236ea and/or HFC-236cb.

For example, the mixture of HF, HFC-1225ye, HFC-236ea and/or HFC-236cbmay be formed by any practical means, such as by feeding at least one ofHFC-236cb or HFC-236ea over a chrome oxide catalyst at elevatedtemperature. The mixture of HF, HFC-1225ye, HFC-236ea and/or HFC-236cbmay be fed to a distillation column. A suitable entrainer is then alsofed to the distillation column, either as a separate stream or by beingmixed in with the HF/HFC-1225ye/HFC-236cb and/or HFC-236ea mixture priorto feeding it to the distillation column. The distillation column isthen operated under conditions sufficient to form a low-boilingazeotrope composition between the entrainer and HF, with the HF andentrainer removed as the column distillate, and the HFC-1225ye,HFC-236ea and/or HFC-236cb recovered from the column bottoms essentiallyfree of HF. The HFC-1225ye may then be separated from the HFC-236eaand/or HFC-236cb by any usual means including conventional distillation,with the HFC-1225ye being recovered as product and with the HFC-236eaand/or HFC-236cb optionally being recycled back to the reaction step toproduce HFC-1225ye.

Thus in another embodiment is provided a process for separating HF froma mixture comprising HFC-1225ye, HF, and at least one of HFC-236ea orHFC-236cb. The process comprises:

-   -   a. adding an entrainer to the mixture comprising HFC-1225ye, HF,        and at least one of HFC-236ea or HFC-236cb thus forming a second        mixture;    -   b. distilling said second mixture in a first distillation step        to form a first distillate composition comprising HF and        entrainer and a first bottoms composition comprising HFC-1225ye        and at least one of HFC-236ea or HFC-236cb;    -   c. condensing said first distillate composition to form two        liquid phases, being (i) an entrainer-rich phase and (ii) an        HF-rich phase; and    -   d. recycling the entrainer-rich phase back to the first        distillation step.        In another embodiment, the process may further comprise feeding        the HF-rich phase to a second distillation step and forming a        second distillate composition comprising an azeotrope of        entrainer and HF and a second bottoms composition comprising HF        essentially free of entrainer. In another embodiment, the        process may further comprise recycling said second distillate        composition back to the two liquid phases.

Referring now to FIG. 4, a stream comprising HF, HFC-1225ye, and atleast one of HFC-236ea or HFC-236cb is fed to a first distillationcolumn 110 via stream 100. An entrainer-rich stream is also fed to thiscolumn via stream 190. Column 110 is operated under conditions to causeHF to distill overhead with the entrainer due to the influence of thelow-boiling HF/entrainer azeotrope. Sufficient entrainer is fed to thisfirst column via stream 190 such that HFC-1225ye and HFC-236ea orHFC-236cb may be obtained essentially free of entrainer and HF as thebottoms from column 110 via stream 120. The HFC-1225ye and HFC-236ea orHFC-236cb in stream 120 may then optionally be separated from each otherby conventional distillation and the HFC-236ea or HFC-236cb optionallyrecycled back to a dehydrofluorination reactor to form HFC-1225ye. Thedistillate from column 110, removed via stream 130, contains essentiallyall of the entrainer and HF in column feeds 100 and 190 and, optionally,some HFC-236ea or HFC-236cb and/or HFC-1225ye. This first distillatestream 130 is condensed by condenser 140 to form stream 150, which isthen mixed with condensed distillate stream 250 from the seconddistillation column and, as needed, additional fresh entrainer added viastream 260. This combined stream is sub-cooled by cooler 160 and sentvia stream 170 to decanter 180 where it separates into separateentrainer-rich and HF-rich liquid fractions which are removed viastreams 190 and 200, respectively. The majority of the HFC-236ea orHFC-236cb and HFC-1225ye present in the decanter partition into theentrainer-rich phase fraction. The entrainer-rich fraction is fed to thefirst distillation column 110 via stream 190. The HF-rich fraction fromthe decanter is fed via stream 200 to a second distillation column 210containing 8 theoretical stages and operated under conditions such thata bottoms stream of HF essentially free of HFC-236ea or HFC-236cb,HFC-1225ye, and entrainer is produced and removed via stream 220. Thedistillate from column 210, removed via stream 230 and containingessentially all of the HFC-236ea or HFC-236cb, HFC-1225ye, and entrainerpresent in the column feed (stream 200) plus the HF not recovered inproduct stream 220, is condensed by condenser 240 and removed via stream250. Condensed distillate stream 250 is combined with both the condenseddistillate stream 150 from the first column and, as needed, freshentrainer, added via stream 260, then cooled and fed to the decanter forfurther separation.

In another embodiment, a hydrofluorocarbon (HFC), which forms ahomogeneous azeotrope with HF, can be separated from a mixturecomprising HF, the HFC and a fluoroolefin by azeotropic distillationusing the fluoroolefin as an entrainer, followed by separation of thefluoroolefin and HF by azeotropic distillation using an added compoundas the entrainer. HF and the fluoroolefin are not required to bepartially miscible at reduced temperatures for such a separation processto work as long as the HF-fluoroolefin azeotrope has a lower boilingpoint than the HF-HFC azeotrope. For illustration purposes, thefluoroolefin is HFC-1225ye and the HFC is HFC-236ea and/or HFC-236cb.

Referring now to FIG. 5, a stream comprising HF, HFC-1225ye, and atleast one of HFC-236ea and HFC-236cb is fed to a first distillationcolumn 30 via stream 10, with the column operated under conditions toapproach the low-boiling HF/HFC-1225ye azeotrope, which is removed asdistillate via streams 50, 70, and 100. This first column can bedesigned and operated in such a way that the near azeotropic distillateis essentially free of HFC-236ea and/or HFC-236cb. By recycling enoughsupplemental HFC-1225ye from the second column bottoms to the firstcolumn via stream 20, essentially all of the HF can be distilledoverhead as the HF/HFC-1225ye azeotrope such that HFC-236cb and/orHFC-236ea are obtained essentially free of HFC-1225ye and HF as thebottoms product from column 30 via stream 40. The HFC-236ea and/orHFC-236cb may then optionally be recycled back to a reactor forproduction of HFC-1225ye, or may be further purified and then recycled.This demonstrates the use of the fluoroolefin as an entrainer to removeHF from an HFC.

As described for FIG. 3, the distillate from the first column may be fedto a second distillation column, mixed with the distillate streams froma second and third column, cooled, and then sent to a decanter, or splitbetween these two destinations. In this embodiment, the distillate fromthe first column 30 is fed via stream 100 to a second column 110. Anentrainer-rich stream is also fed to this second column via stream 190.Distillation column 110 is operated under conditions such that thedistillate, removed via stream 130, contains essentially all of theentrainer and HF in the column feeds 100 and 190 and produces anHFC-1225ye bottoms product essentially free of HF and entrainer which isremoved via stream 120. Part of the HFC-1225ye bottoms stream 120 isrecycled to the first column via stream 20, as previously described, andthe rest becomes the purified HFC-1225ye product removed via stream 125.Distillate stream 130 is condensed by condenser 140 to form stream 150,which is then mixed with the condensed distillate stream 250 from thesecond distillation column and, as needed, fresh entrainer added viastream 260. This combined stream is cooled by cooler 160 and sent viastream 170 to decanter 180 where it separates into separateentrainer-rich and HF-rich liquid fractions, which are removed viastreams 190 and 200, respectively. The majority of the HFC-1225yepresent in the decanter partitions into the entrainer-rich phasefraction. The decanter entrainer-rich fraction is fed to column 110 viastream 190. The decanter HF-rich fraction is fed, via stream 200, to athird distillation column 210 operated under conditions which produce abottoms product consisting of HF essentially free of HFC-1225zc and theentrainer, which is removed via stream 220. The distillate from column210, which is removed via stream 230 and contains essentially all of theHFC-1225ye and entrainer present in the column feed (stream 200) and anyHF not recovered in product stream 220, is condensed by condenser 240,forming stream 250. Condensed distillate stream 250 is combined withboth the condensed distillate stream 150 from the second column and, asneeded, fresh entrainer, added via stream 260, then cooled and fed tothe decanter via stream 170 for further separation.

In one embodiment, entrainers for HF separation from HFC-1225ye andoptionally HFC-236ea and/or HFC-236cb include: CFC-115(chloropentafluoroethane), CFC-114(1,2-dichloro-1,1,2,2-tetrafluoroethane), CFC-114a(1,1-dichloro-1,2,2,2-tetrafluoroethane), HCFC-21(dichlorofluoromethane), HCFC-124 (1-chloro-1,2,2,2-tetrafluoroethane),HCFC-124a (1-chloro-1,1,2,2-tetrafluoroethane), HCFC-133a(1-chloro-2,2,2-trifluoroethane), HCFC-142b(1-chloro-1,1-difluoroethane), HCFC-1122(1-chloro-2,2-difluoroethylene), HFC-1234ze(1,3,3,3-tetrafluoro-1-propene), HFC-1123 (trifluoroethylene),HFC-1234yf (2,3,3,3-tetrafluoro-1-propene), PFC-218 (octafluoroethane),PFC-C216 (trifluorocyclopropane), cis- and trans-PFC-1318(octafluoro-2-butene), PFC-1216 (hexafluoropropene, HFP), PFC-C318(octafluorocyclobutane), PFC-31-10my (decafluorobutane), PFC-2316(hexafluorobutadiene), PEVE (perfluoroethylvinyl ether), PMVE(perfluoromethylvinyl ether), SF₆ (sulfur hexafluoride), Cl₂ (Chlorine),Cyclopropane, C₂H₆ (Ethane), propane, n-butane, isobutane,2,2-dimethylpropane, 1-butene, isobutene, 1,3-butadiene, cis- andtrans-2-butene, 1-butyne, vinylacetylene, hexafluoroacetone,1,1-difluorodimethyl ether, pentafluoroethylmethyl ether,tetrafluorodimethyl ether, and mixtures thereof. In another embodiment,the entrainers that are effective for separation of HF from HFC-1225yeinclude n-propane and ethane.

5. Other Fluoroolefins and Separation Processes Utilizing Azeotropeswith HF

Other fluoroolefin/HF azeotropes have been disclosed that may be used inseparation processes as described herein for HFC-1225ye and HFC-236.

U.S. Patent Publication no. 2007-0100173 A1 discloses the azeotrope andazeotrope-like (also known as near-azeotrope) compositions forHFC-1234ze (1,3,3,3-tetrafluoropropene) and HF. These azeotrope andazeotrope-like compositions may be used in processes for separating afluoroolefin from a mixture comprising HF and fluoroolefin.Additionally, as HFC-1234ze may be prepared by dehydrofluorination ofHFC-245fa (1,1,1,3,3-pentafluoropropane) or HFC-245eb(1,1,1,2,3-pentafluoropropane) the compositions as described therein maybe used in similar methods for separation or purification of HFC-1234zefrom mixtures comprising HFC-1234ze, HF and at least one of HFC-245fa orHFC-245eb.

In another embodiment, a process is provided for the separation ofHFC-1234ze from a mixture of HFC-1234ze, HF, and at least one ofHFC-245fa or HFC-245eb, said process comprising:

a) subjecting said mixture to a first distillation step, whereinadditional HFC-1234ze is fed from a second distillation step, to form afirst distillate comprising an azeotrope of HFC-1234ze and HF and afirst bottoms composition comprising at least one of HFC-245fa orHFC-245eb;

b) feeding said first distillate to a second distillation step to form asecond distillate comprising an azeotrope of HFC-1234ze and HF and asecond bottoms composition comprising HFC-1234ze essentially free of HF;

c) condensing said second distillate to form two liquid phases, being i)an HF-rich phase and ii) an HFC-1234ze-rich phase; and

d) recycling the HFC-1234ze-rich phase from (c) back to the firstdistillation step. In another embodiment, the process may furthercomprise feeding the HF-rich phase to a third distillation step to forma third distillate comprising an azeotrope of HFC-1234ze and HF and athird bottoms composition comprising HF essentially free of HFC-1234ze.

In another embodiment is provided a process for separating HF from amixture comprising HFC-1234ze, HF, and at least one of HFC-245fa orHFC-245eb. The process comprises:

-   -   a. adding an entrainer to the mixture comprising HFC-1234ze, HF,        and at least one of HFC-245fa or HFC-245eb thus forming a second        mixture;    -   b. distilling said second mixture in a first distillation step        to form a first distillate composition comprising HF and        entrainer and a first bottoms composition comprising HFC-1234ze        and at least one of HFC-245fa or HFC-245eb;    -   c. condensing said first distillate composition to form two        liquid phases, being (i) an entrainer-rich phase and (ii) an        HF-rich phase; and    -   d. recycling the entrainer-rich phase back to the first        distillation step.        In another embodiment, the process may further comprising        feeding the HF-rich phase to a second distillation step and        forming a second distillate composition comprising an azeotrope        of entrainer and HF and a second bottoms composition comprising        HF essentially free of entrainer. In another embodiment, the        process may further comprising recycling said second distillate        composition back to the two liquid phases.

U.S. Patent Publication no. 2007-0100175 A1 discloses the azeotrope andazeotrope-like (also known as near-azeotrope) compositions forHFC-1234yf (2,3,3,3-tetrafluoropropene) and HF. These azeotrope andazeotrope-like compositions may be used in processes for separating afluoroolefin from a mixture comprising HF and fluoroolefin.Additionally, as HFC-1234yf may be prepared by dehydrofluorination ofHFC-245cb (1,1,1,2,2-pentafluoropropane) or HFC-245eb(1,1,1,2,3-pentafluoropropane) the compositions as described therein maybe used in similar methods for separation or purification of HFC-1234yffrom mixtures comprising HFC-1234yf, HF and at least one of HFC-245cb orHFC-245eb.

In another embodiment, a process is provided for the separation ofHFC-1234yf from a mixture of HFC-1234yf, HF, and at least one ofHFC-245cb or HFC-245eb, said process comprising:

a) subjecting said mixture to a first distillation step, whereinadditional HFC-1234yf is fed from a second distillation step, to form afirst distillate comprising an azeotrope of HFC-1234yf and HF and afirst bottoms composition comprising at least one of HFC-245cb orHFC-245eb;

b) feeding said first distillate to a second distillation step to form asecond distillate comprising an azeotrope of HFC-1234yf and HF and asecond bottoms composition comprising HFC-1234yf essentially free of HF;

c) condensing said second distillate to form two liquid phases, being i)an HF-rich phase and ii) an HFC-1234yf-rich phase; and

d) recycling the HFC-1234yf-rich phase from (c) back to the firstdistillation step. In another embodiment, the process may furthercomprise feeding the HF-rich phase to a third distillation step to forma third distillate comprising an azeotrope of HFC-1234yf and HF and athird bottoms composition comprising HF essentially free of HFC-1234yf.

In another embodiment, a process is provided for separating HF from amixture comprising HFC-1234yf, HF, and at least one of HFC-245cb orHFC-245eb. The process comprises:

-   -   a. adding an entrainer to the mixture comprising HFC-1234yf, HF,        and at least one of HFC-245cb or HFC-245eb thus forming a second        mixture;    -   b. distilling said second mixture in a first distillation step        to form a first distillate composition comprising HF and        entrainer and a first bottoms composition comprising HFC-1234yf        and at least one of HFC-245cb or HFC-245eb;    -   c. condensing said first distillate composition to form two        liquid phases, being (i) an entrainer-rich phase and (ii) an        HF-rich phase; and    -   d. recycling the entrainer-rich phase back to the first        distillation step.

In another embodiment, the process may further comprise feeding theHF-rich phase to a second distillation step and forming a seconddistillate composition comprising an azeotrope of entrainer and HF and asecond bottoms composition comprising HF essentially free of entrainer.In another embodiment, the process may further comprise recycling saidsecond distillate composition back to the two liquid phases.

U.S. Patent Publication no. US2007-0099811 A1 discloses the azeotropeand azeotrope-like (also known as near-azeotrope) compositions forHFC-1429 (nonafluoropentene) and HF. These azeotrope and azeotrope-likecompositions may be used in processes for separating a fluoroolefin froma mixture comprising HF and fluoroolefin. Additionally, as HFC-1429 maybe prepared by dehydrofluorination of HFC-43-10mee(1,1,1,2,3,4,4,5,5,5-decafluoropentane) the compositions as describedtherein may be used in similar methods for separation or purification ofHFC-1429 from mixtures comprising HFC-1429, HF and HFC-43-10mee.

In one embodiment, a process is provided for the separation of HFC-1429from a mixture of HFC-1429, HF, and HFC-43-10mee, said processcomprising:

a) subjecting said mixture to a first distillation step, whereinadditional HFC-1429 is fed from a second distillation step, to form afirst distillate comprising an azeotrope of HFC-1429 and HF and a firstbottoms composition comprising HFC-43-10mee;

b) feeding said first distillate to a second distillation step to form asecond distillate comprising an azeotrope of HFC-1429 and HF and asecond bottoms composition comprising HFC-1429 essentially free of HF;

c) condensing said second distillate to form two liquid phases, being i)an HF-rich phase and ii) an HFC-1429-rich phase; and

d) recycling the HFC-1429-rich phase from (c) back to the firstdistillation step. In another embodiment, the process may furthercomprise feeding the HF-rich phase to a third distillation step to forma third distillate comprising an azeotrope of HFC-1429 and HF and athird bottoms composition comprising HF essentially free of HFC-1429.

In one embodiment, a process is provided for separating HF from amixture comprising HFC-1429, HF, and HFC-43-10mee. The processcomprises:

-   -   a. adding an entrainer to the mixture comprising HFC-1429, HF,        and HFC-43-10mee thus forming a second mixture;    -   b. distilling said second mixture in a first distillation step        to form a first distillate composition comprising HF and        entrainer and a first bottoms composition comprising HFC-1429        and HFC-43-10mee;    -   c. condensing said first distillate composition to form two        liquid phases, being (i) an entrainer-rich phase and (ii) an        HF-rich phase; and    -   d. recycling the entrainer-rich phase back to the first        distillation step.

In another embodiment, the process may further comprise feeding theHF-rich phase to a second distillation step and forming a seconddistillate composition comprising an azeotrope of entrainer and HF and asecond bottoms composition comprising HF essentially free of entrainer.In another embodiment, the process may further comprising recycling saidsecond distillate composition back to the two liquid phases.

U.S. Patent Publication no. 2006-0116538 A1 discloses the azeotrope andazeotrope-like (also known as near-azeotrope) compositions forHFC-1225zc (1,1,3,3,3-pentafluoropropene) and HF. These azeotrope andazeotrope-like compositions may be used in processes for separating afluoroolefin from a mixture comprising HF and fluoroolefin.Additionally, as HFC-1225zc may be prepared by dehydrofluorination ofHFC-236fa (1,1,1,3,3,3-hexafluoropropane) or HFC-236ea(1,1,1,2,3,3-hexafluoropropane) the compositions as described thereinmay be used in similar methods for separation or purification ofHFC-1225zc from mixtures comprising HFC-1225zc, HF and at least one ofHFC-236fa or HFC-236ea.

In one embodiment, a process is provided for the separation ofHFC-1225zc from a mixture of HFC-1225zc, HF, and at least one ofHFC-236fa or HFC-236ea, said process comprising:

a) subjecting said mixture to a first distillation step, whereinadditional HFC-1225zc is fed from a second distillation step, to form afirst distillate comprising an azeotrope of HFC-1225zc and HF and afirst bottoms composition comprising at least one of HFC-236fa orHFC-236ea;

b) feeding said first distillate to a second distillation step to form asecond distillate comprising an azeotrope of HFC-1225zc and HF and asecond bottoms composition comprising HFC-1225zc essentially free of HF;

c) condensing said second distillate to form two liquid phases, being i)an HF-rich phase and ii) an HFC-1225zc-rich phase; and

d) recycling the HFC-1225zc-rich phase from (c) back to the firstdistillation step. In another embodiment, the process may furthercomprise feeding the HF-rich phase to a third distillation step to forma third distillate comprising an azeotrope of HFC-1225zc and HF and athird bottoms composition comprising HF essentially free of HFC-1225zc.

In one embodiment, a process is provided for separating HF from amixture comprising HFC-1225zc, HF, and at least one of HFC-236fa orHFC-236ea. The process comprises:

-   -   a. adding an entrainer to the mixture comprising HFC-1225zc, HF,        and at least one of HFC-236fa or HFC-236ea thus forming a second        mixture;    -   b. distilling said second mixture in a first distillation step        to form a first distillate composition comprising HF and        entrainer and a first bottoms composition comprising HFC-1225zc        and at least one of HFC-236fa or HFC-236ea;    -   c. condensing said first distillate composition to form two        liquid phases, being (i) an entrainer-rich phase and (ii) an        HF-rich phase; and    -   d. recycling the entrainer-rich phase back to the first        distillation step.        In another embodiment, the process may further comprise feeding        the HF-rich phase to a second distillation step and forming a        second distillate composition comprising an azeotrope of        entrainer and HF and a second bottoms composition comprising HF        essentially free of entrainer. In another embodiment, the        process may further comprise recycling said second distillate        composition back to the two liquid phases.

EXAMPLES

The concepts described herein will be further described in the followingexamples, which do not limit the scope of the invention described in theclaims.

Example 1 Dehydrofluorination of HFC-236ea to HFC-1225ye (E and ZIsomers) Over Carbonaceous Catalyst

To a Hastelloy nickel alloy reactor (1.0″ OD×0.854″ ID×9.5″ L) wascharged 14.32 g (25 mL) of spherical (8 mesh) three dimensional matrixporous carbonaceous material prepared substantially as described in U.S.Pat. No. 4,978,649. The packed portion of the reactor was heated by a5″×1″ ceramic band heater clamped to the outside of the reactor. Athermocouple, positioned between the reactor wall and the heatermeasured the reactor temperature. After charging the reactor with thecarbonaceous material, nitrogen (10 mL/min) was passed through thereactor and the temperature was raised to 200° C. during a period of onehour and maintained at this temperature for an additional 4 hours. Thereactor temperature was then raised to the desired operating temperatureand a flow of HFC-236ea and nitrogen was started through the reactor.

A portion of the total reactor effluent was sampled on-line for organicproduct analysis using a gas chromatograph equipped with a massselective detector (GC-MS). The bulk of the reactor effluent containingorganic products and also inorganic acid, such as HF, was treated withaqueous caustic for neutralization.

The results obtained in GC mole percent are summarized in Table 3.

TABLE 4 Reactor 236ea Mole Percent Temp. feed N₂ _(—) feed Un-  (° C.)(mL/min) (mL/min) Z-1225ye E-1225ye 236ea knowns 200 10 20 0.03 ND 99.97ND 250 10 20 0.2 0.03 99.8 ND 300 10 20 1.4 0.22 98.4 0.01 350 10 20 5.40.96 93.1 0.5 400 10 20 38.1 9.0 51.7 1.1 400 10 10 37.9 8.7 51.6 1.8400 10 5 42.6 9.5 46.7 1.2 400 10 40 13.2 2.5 71.6 12.7 ND = notdetected

Example 2 Azeotropic Distillation for the Separation of HFC-1225ye fromHF without an Entrainer

Example 2 demonstrates that HF may be separated from HFC-1225ye byazeotropic distillation with no entrainer. Referring now to FIG. 1, acomposition comprising HF and HFC-1225ye is fed to a first column 110via stream 100. This first column contains 8 theoretical stages and isoperated under appropriate conditions to approach the low-boilingHF/HFC-1225ye azeotrope. Because HF is being fed to this first column inexcess of that needed to form the azeotrope with the HFC-1225ye, HF isrecovered as a product stream out the bottoms of the column via stream120, while a composition near to the HF/HFC-1225ye azeotrope isrecovered as distillate via stream 130. Stream 130 is condensed in 140,mixed with the nearly azeotropic composition recycled from the secondcolumn via stream 250 and the combined stream is sub-cooled in cooler160 and sent to decanter 180 where the combined stream 170 separatesinto separate HF-rich (190) and HFC-1225ye-rich (200) streams. Stream190 is recycled to the first column as reflux. Stream 200 is fed to thetop stage of a second distillation column 210, containing 19 theoreticalstages and operated under conditions to approach the HF/HFC-1225yeazeotrope. Because HFC-1225ye is being fed to this second column inexcess of that needed to form the low-boiling HF/HFC-1225ye azeotrope,HFC-1225ye is recovered as a product stream out the bottoms of thecolumn via stream 220 while a composition close to the HF/HFC-1225yeazeotrope is recovered as distillate via stream 230. Stream 230 iscondensed in 240, mixed with the nearly azeotropic composition from thefirst column via stream 150 and fed to cooler 160 and then decanter 180.

The data in Table 5 were calculated using measured and calculatedthermodynamic properties.

TABLE 5 Second First HFC- dist. col. dist. col. HF rich 1225ye BottomFirst bottom phase rich phase (HFC- Component First dist. column (HF(from (from Second 1225ye or variable col. feed distillate product)decanter) decanter) distillate product) Stream No. 100 130 120 190 200230 220 HF, wt % 13.2 8.1 100 40.8 1.3 7.5 1 ppm HFC- 86.8 91.9 10 ppm59.2 98.7 92.5 100 1225ye, wt % Temp, ° C. 30.0 46.8 102.2 −40.0 −40.046.6 53.2 Pres, psia 165 160 160 159 159 160 160 (kPa)

Example 3 Azeotropic Distillation for the Separation of HFC-1225ye fromHF Using Propane as the Entrainer

Example 3 demonstrates that HF may be separated from HFC-1225ye byazeotropic distillation using propane as the entrainer. This ternarymixture forms three minimum-boiling binary azeotropes and aminimum-boiling ternary azeotrope.

Referring now to FIG. 2, a composition consisting of HF and HFC-1225yeis fed to a first column 110 containing 8 theoretical stages via stream100. An HF-rich and propane-lean composition is also fed to the topstage of column 110 via stream 190. Because the combined amount of HF instreams 100 and 190 is in excess of that needed to form the low-boilingHF/HFC-1225ye azeotrope, HF is recovered as a product stream essentiallyfree of both HFC-1225ye and propane from the bottom of column 110 viastream 120. A composition near the HF/HFC-1225ye azeotrope is recoveredas the distillate via stream 130. Stream 130 is condensed by condenser140 forming stream 150 and mixed with both the condensed distillatestream 250 from a second distillation column and, as needed, additionalpropane added via stream 260. Combined streams 150, 250, and 260 aresent to cooler 160 and then to decanter 180 where the sub-cooled liquidstream 170 separates into HF-rich and propane-rich liquid phasefractions which are removed via streams 190 and 200, respectively. TheHFC-1225ye present in the decanter primarily distributes into thepropane-rich liquid phase fraction. Stream 190 is recycled to the firstcolumn. The HF-lean liquid phase fraction in the decanter is fed to thetop stage of a second distillation column 210 via stream 200. Becausethe amount of HFC-1225ye in stream 200 is in excess of that needed toform the low-boiling propane/HFC-1225ye, HFC-1225ye/HF, andpropane/HFC-1225ye/HF azeotropes, i.e., the composition of stream 200lies in the distillation region bounded by these three azeotropecompositions and pure HFC-1225ye, HFC-1225ye is recovered as a productstream essentially free of both HF and propane from the bottom of column210 via stream 220. A ternary composition enriched in propane relativeto stream 200 and in the same distillation region leaves the top of thesecond column as the distillate via stream 230. Stream 230 is condensedby condenser 240, forming stream 250, and combined with streams 150 and260 as previously described.

The data in Table 6 were calculated using measured and calculatedthermodynamic properties

TABLE 6 First dist. Propane col. HF rich rich Second dist. First bottomphase phase col. Bottom Component or dist. col. First (HF (from (fromSecond (HFC-1225ye variable feed distillate product) decanter) decanter)distillate product) Stream No. 100 130 120 190 200 230 220 HF, wt % 13.28.1 100 39.2 0.6 0.9 <1 ppm HFC-1225ye, 86.8 91.7  1 ppm 59.5 84.7 77.4100 wt % Propane, wt % 0 0.2 <1 ppm 1.3 14.7 21.7 10 ppm Temp, ° C. 25.016.4 66.6 −20.0 −20.0 11.6 20.8 Pres, psia (kPa) 115 65 65 65 65 65 65

Example 4 Azeotropic Distillation for Separating HFC-1225ye and HF fromHFC-236ea

A mixture of HF, HFC-1225ye, and HFC-236ea is fed to a distillationcolumn for the purpose of purification of the HFC-236ea. HFC-236ea andHF form a low-boiling azeotrope which does not separate into two liquidphases and which prevents all of the HF from being removed from mixturescomprising HFC-236ea by ordinary fractional distillation. The boilingtemperature of the HF/HFC-236ea azeotrope is higher than that of theHF/HFC-1225ye azeotrope. The distillation column in this example isoperated under conditions to form a composition approaching that of thelow-boiling HF/HFC-1225ye azeotrope at the top of the column. However,in this example, there is insufficient HFC-1225ye present to remove allof the HF in the distillate at the near HF/HFC-1225ye azeotropecomposition. Consequently, some HF remains with the HFC-236ea exitingthe column bottoms.

The data in Table 7 were obtained by calculation using measured andcalculated thermodynamic properties.

TABLE 7 Component or Column Column overhead Column variable feed(distillate) bottoms HFC-236ea, mol % 33.4 1 ppm 66.0 HFC-1225ye, mol %33.3 67.4 180 ppm HF, mol % 33.3 32.6 34.0 Temp, ° C. — −10.0 13.8Pressure, psi — 24.7 (170) 26.7 (184) (kPa)

Example 5 Azeotropic Distillation for Separating HFC-1225ye and HF fromHFC-236ea

A mixture of HF, HFC-1225ye, and HFC-236ea is fed to a distillationcolumn for the purpose of purification of the HFC-236ea. Thedistillation column in this example is operated under conditions to forma composition approaching that of the low-boiling HF/HFC-1225yeazeotrope at the top of the column. In contrast to Example 4, there isenough HFC-1225ye present in the feed mixture such that all of the HFexits in the distillate at a composition close to the HF/HFC-1225yeazeotrope, leaving the HFC-236ea obtained as column bottoms essentiallyfree of HF.

The data in Table 8 were obtained by calculation using measured andcalculated thermodynamic properties.

TABLE 8 Component or Column Column overhead Column variable feed(distillate) bottoms HFC-236ea, mol % 24.4 1 ppm 99.99 HFC-1225ye, mol %51.2 67.7 68 ppm HF, mol % 24.4 32.3 trace Temp, ° C. — −8.3 21.8 Pressure, psi — 24.7 (170) 26.7 (184) (kPa)

Example 6

This Example shows how HF, HFC-1225ye, HFC-236ea and/or HFC-236cb may beseparated using HFC-1225ye as an entrainer. One possible source for sucha mixture is in an HFC-236ea and/or HFC-236cb dehydrofluorinationprocess operated with partial conversion. Like HFC-236ea, HFC-236cbforms an azeotrope with HF that does not separate into two liquid phasesand that has a higher boiling point than the HF/HFC-1225ye azeotrope.

Referring now to FIG. 3, a stream comprising HF, HFC-1225ye, and atleast one of HFC-236ea and HFC-236cb is fed to the 33^(rd) stage fromthe top of a first distillation column containing 40 theoretical stagesvia stream 10, with the column operated under conditions to approach thelow-boiling HF/HFC-1225ye azeotrope, which is removed as distillate viastreams 50, 70, and 90. Enough supplemental HFC-1225ye is recycled fromthe second column bottoms to 12^(th) stage from the top of this firstcolumn via stream 20 to enable all of the HF to be removed from theHFC-236cb and/or HFC-236ea. The HFC-236cb and/or HFC-236ea are obtainedessentially free of HFC-1225ye and HF as the bottoms product from thiscolumn via stream 40.

The near HF/HFC-1225ye azeotropic composition in stream 50 is condensedand divided into reflux (80) and distillate (90) streams. Column 30 isoperated with a reflux ratio of 9.0. Distillate stream 90 may be fed toa second distillation column 110 via stream 100 as shown and indicated,mixed with distillate streams 150 and 250 from the second and thirdcolumns, respectively, and sent to cooler 160 and decanter 180, or bedivided between these two destinations. Because of the desire to removeall of the HF overhead in column 30, excess HFC-1225ye would be recycledto column 30, making the composition of streams 50, 70, 80, 90, and 100lie on the HFC-1225ye-rich side of the azeotrope. Therefore, ifdistillate stream 90 is sent via stream 100 to a second distillationcolumn, it should be sent to the column which produces purifiedHFC-1225ye as the bottoms product.

For this example, distillate stream 90 via stream 260 is mixed withdistillate streams 150 and 250 from the second and third columns,respectively, and sent to cooler 160, forming sub-cooled stream 170,which is fed to decanter 180. In the decanter, stream 170 separates intoHFC-1225ye-rich and HF-rich liquid fractions, which are removed asstreams 190 and 200. The HFC-1225ye-rich stream from the decanter is fedvia stream 190 to a second distillation column 110 containing 19theoretical stages and operated under conditions to approach theHFC-1225ye/HF azeotrope, which is distilled overhead as distillatestream 130, condensed in condenser 140, and mixed with the distillatesfrom the first and third columns via stream 150. Column 110 produces abottoms stream of HFC-1225ye essentially free of HF via stream 120. Partof the HFC-1225ye bottoms stream 120 is recycled to the first column viastream 20, as previously described, and the rest becomes the purifiedHFC-1225ye product removed via stream 125. The HF-rich stream from thedecanter is fed via stream 200 to a third distillation column 210containing 9 theoretical stages and operated under conditions toapproach the HFC-1225ye/HF azeotrope, which is distilled overhead asdistillate as stream 230 which is condensed in condenser 250 and mixedwith the distillates from the first and second columns via stream 250.Column 210 produces a bottoms stream of HF essentially free ofHFC-1225ye via stream 220.

The data in Table 9 were obtained by calculation using measured andcalculated thermodynamic properties.

TABLE 9 1225- First First Second Second rich HF-rich Third ThirdComponent Feed btms Dist btms Dist phase phase btms Dist or variable(10) (40) (50) (120) (130) (190) (200) (220) (230) HF, wt % 4.03 4 ppm5.73 1 ppm 7.36 1.32 40.76 100 8.52 HFC-236cb, 71.33 99.71 1 ppm 1 ppm<1 ppm 1 ppm <1 ppm <1 ppm <1 ppm wt % HFC- 24.64 0.29 94.27 100 92.6498.68 59.24 1 ppm 91.48 1225ye, wt % Temp, ° C. 27.7 35.8 11.8 37.1 31.6−40.0 −40.0 84.9 32.2 Pressure, 60.6 54.8 54.8 104.8 104.7 104.7 104.7104.8 104.7 psia

Example 7

This Example shows one way in which HF may be separated from afluoroolefin and its dehydrofluorination precursor, for exampleHFC-1225ye and HFC-236ea and/or HFC-236cb or HFC-1225zc and HFC-236fa,by azeotropic distillation using an added entrainer. Like both HFC-236cband HFC-236ea, HFC-236fa forms an azeotrope with HF that does notseparate into two liquid phases and that has a higher boilingtemperature than the HF/HFC-1225zc azeotrope. The composition of feedmixture in this example is such as one might obtain from adehydrofluorination reactor operated with partial conversion, i.e., itcontains equimolar amounts of HF and fluoroolefin.

Referring now to FIG. 4, a stream comprising HF, HFC-1225zc, andHFC-236fa is fed to a first distillation column 110 via stream 100. Anentrainer-rich stream is also fed to this column via stream 190. In thisexample, CFC-115 is used as the entrainer. CFC-115 forms a low-boilingazeotrope with HF that separates into two liquid phases uponcondensation and whose boiling temperature is lower than the otherazeotropes in the mixture

Column 110 contains 34 theoretical stages and is operated underconditions to cause HF to distill overhead with the entrainer due to theinfluence of the low-boiling HF/CFC-115 azeotrope. Sufficient CFC-115 isfed to this first column via stream 190 such that HFC-1225zc andHFC-236fa may be obtained essentially free of CFC-115 and HF as thebottoms from column 110 via stream 120. The HFC-1225zc and HFC-236fa instream 120 may then optionally be separated from each other byconventional distillation and the HFC-236fa optionally recycled back toa dehydrofluorination reactor to form HFC-1225zc. The distillate fromcolumn 110, removed via stream 130, contains essentially all of theCFC-115 and HF in column feeds 100 and 190 and, optionally, someHFC-236fa and/or HFC-1225zc. This first distillate stream 130 iscondensed by condenser 140 to form stream 150, which is then mixed withcondensed distillate stream 250 from the second distillation column and,as needed, additional fresh CFC-115 added via stream 260. This combinedstream is sub-cooled by cooler 160 and sent via stream 170 to decanter180 where it separates into separate entrainer-rich and HF-rich liquidfractions which are removed via streams 190 and 200, respectively. Themajority of the HFC-236fa and HFC-1225zc present in the decanterpartition into the CFC-115-rich phase fraction. The entrainer-richfraction is fed to the first distillation column 110 via stream 190. TheHF-rich fraction from the decanter is fed via stream 200 to a seconddistillation column 210 containing 8 theoretical stages and operatedunder conditions such that a bottoms stream of HF essentially free ofHFC-236fa, HFC-1225zc, and CFC-115 is produced and removed via stream220. The distillate from column 210, removed via stream 230 andcontaining essentially all of the HFC-236fa, HFC-1225zc, and CFC-115present in the column feed (stream 200) plus the HF not recovered inproduct stream 220, is condensed by condenser 240 and removed via stream250. Condensed distillate stream 250 is combined with both the condenseddistillate stream 150 from the first column and, as needed, freshentrainer, added via stream 260, then cooled and fed to the decanter forfurther separation.

The data in Table 10 were obtained by calculation using measured andcalculated thermodynamic properties.

TABLE 10 En- train- First er- HF- col First rich rich Second SecondComponent Feed btm Dist phase phase col btm Dist or variable (100) (120)(130) (190) (200) (220) (230) HFC-236fa, 57.14 60.56 11.81 12.19 6.51 <1ppm 8.05 wt % HFC- 37.22 39.44 20.30 20.95 8.63 <1 ppm 10.67 1225zc, wt% HF, wt % 5.64 <1 ppm 4.05 0.94 66.30 100.0  58.33 CFC-115, 0   1 ppm63.84 65.91 18.52 <1 ppm 22.95 wt % Temp, ° C. 30.0 29.2  7.1 −25.0−25.0 66.7 58.2 Pres, psia 114.7 64.8  64.7 64.7 64.7 64.7 64.7

Example 8

This Example shows how an HFC which forms a homogeneous azeotrope withHF can be separated from a mixture comprising HF, the HFC and afluoroolefin by azeotropic distillation using the fluoroolefin as anentrainer, followed by separation of the fluoroolefin and HF byazeotropic distillation using an added compound as the entrainer. HF andthe fluoroolefin are not required to be partially miscible at reducedtemperatures for such a separation process to work as long as theHF-fluoroolefin azeotrope has a lower boiling point than the HF-HFCazeotrope. For illustration purposes, the fluoroolefin is HFC-1225ye andthe HFC is HFC-236ea and/or HFC-236cb.

Referring now to FIG. 5, a stream comprising HF, HFC-1225ye, and atleast one of HFC-236ea and HFC-236cb is fed to a first distillationcolumn 30 via stream 10, with the column operated under conditions toapproach the low-boiling HF/HFC-1225ye azeotrope, which is removed asdistillate via streams 50, 70, and 100. This first column can bedesigned and operated in such a way that the near azeotropic distillateis essentially free of HFC-236ea and/or HFC-236cb. By recycling enoughsupplemental HFC-1225ye from the second column bottoms to the firstcolumn via stream 20, essentially all of the HF can be distilledoverhead as the HF/HFC-1225ye azeotrope such that HFC-236cb and/orHFC-236ea are obtained essentially free of HFC-1225ye and HF as thebottoms product from column 30 via stream 40. The HFC-236ea and/orHFC-236cb may then optionally be recycled back to a reactor forproduction of HFC-1225ye, or may be further purified and then recycled.This demonstrates the use of the fluoroolefin as an entrainer to removeHF from an HFC.

As described in Example 6, the distillate from the first column may befed to a second distillation column, mixed with the distillate streamsfrom a second and third column, cooled, and then sent to a decanter, orsplit between these two destinations. For this example, the distillatefrom the first column 30 is fed via stream 100 to a second column 110.An entrainer-rich stream is also fed to this second column via stream190. Distillation column 110 is operated under conditions such that thedistillate, removed via stream 130, contains essentially all of theentrainer and HF in the column feeds 100 and 190 and produces anHFC-1225ye bottoms product essentially free of HF and entrainer which isremoved via stream 120. Part of the HFC-1225ye bottoms stream 120 isrecycled to the first column via stream 20, as previously described, andthe rest becomes the purified HFC-1225ye product removed via stream 125.Distillate stream 130 is condensed by condenser 140 to form stream 150,which is then mixed with the condensed distillate stream 250 from thesecond distillation column and, as needed, fresh entrainer added viastream 260. This combined stream is cooled by cooler 160 and sent viastream 170 to decanter 180 where it separates into separateentrainer-rich and HF-rich liquid fractions, which are removed viastreams 190 and 200, respectively. The majority of the HFC-1225yepresent in the decanter partitions into the entrainer-rich phasefraction. The decanter entrainer-rich fraction is fed to column 110 viastream 190. The decanter HF-rich fraction is fed, via stream 200, to athird distillation column (210) operated under conditions which producea bottoms product consisting of HF essentially free of HFC-1225ye andthe entrainer, which is removed via stream 220. The distillate fromcolumn 210, which is removed via stream 230 and contains essentially allof the HFC-1225ye and entrainer present in the column feed (stream 200)and any HF not recovered in product stream 220, is condensed bycondenser 240, forming stream 250. Condensed distillate stream 250 iscombined with both the condensed distillate stream 150 from the secondcolumn and, as needed, fresh entrainer, added via stream 260, thencooled and fed to the decanter via stream 170 for further separation.

Example 9

This example shows how an HFC that forms a homogeneous azeotrope with HFand a fluoroolefin that forms an azeotrope with HF and is partiallymiscible with HF can both be separated from a mixture comprising HF, theHFC and the fluoroolefin by azeotropic distillation using thefluoroolefin as an entrainer as long as the HF-fluoroolefin azeotropehas a lower boiling point than the HF-HFC azeotrope. For illustrationpurposes, in this example the fluoroolefin is HFC-1225ye, the HFC isHFC-236ea and/or HFC-236cb, and the feed mixture has a composition suchas might be obtained from a dehydrofluorination reactor operated withpartial conversion, that is, the mixture contains equimolar amounts ofHF and the fluoroolefin.

As in Examples 6 and 8, the HFC-236ea and/or HFC-236cb present areseparated from HF and HFC-1225ye by azeotropic distillation in a firstdistillation column (20) using the HFC-1225ye in the feed mixture as theentrainer. As before, additional HFC-1225ye is needed to distill all ofthe HF away from the HFC-236ea and/or HFC-236cb. Referring now to FIG.6, the difference in this example is that a first cooler (60) and afirst decanter (70) are added after the first distillation column'scondenser (50) such that the distillate separates into HF-rich andHFC-1225ye-rich liquid phase fractions in the decanter, which areremoved via streams 80 and 90, respectively. Part of the HFC-1225ye-richstream (90) is returned to the first column as reflux via stream 95 andthe remaining portion is fed to a second distillation column (110) viastream 100 where it is separated into an HFC-1225ye bottoms product,removed via stream 120, that is essentially free of HF and a distillatecomposition near to the HF/HFC-1225ye azeotrope, removed via stream 130,as described in Example 8. Because the reflux stream (95) is enriched inHFC-1225ye relative to the HFC-1225ye/HF azeotropic composition, thereflux stream (95) supplies the additional HFC-1225ye needed to make theHFC-236ea and/or HFC-236cb bottoms product from the first column,removed via stream 30, essentially free of HF, thereby reducing theamount of purified HFC-1225ye that must be recycled from the secondcolumn to the first column. As shown in FIG. 6, at sufficiently highreflux flows, the need for recycling any of the purified HFC-1225ye fromthe bottom of the second column to the first column can be completelyeliminated. The first decanter's HF-rich phase fraction is fed to athird distillation column (210) via stream 80. Both feeds (streams 80and 200) to the third column have compositions containing excess HFrelative to the HF/HFC-1225ye azeotrope so that an HF bottoms productessentially free of HFC-1225ye may be obtained in column 210 and removedvia stream 220. The distillate from the third column has a compositionnear to the HF/HFC-1225ye azeotrope and is removed via stream 230. As inearlier examples, the distillates (streams 130 and 230) from columns 110and 210 are condensed in condensers 140 and 240, forming streams 150 and250, respectively, mixed together, and sent first to a second cooler(160) and then to a second decanter (180) where separate HFC-1225ye-richand HF-rich liquid phase fractions are formed. The HFC-1225ye-richfraction is removed from decanter 180 via stream 190 and fed to thesecond column 110 for further separation. The HF-rich fraction isremoved from decanter 180 via stream 200 and fed to the third column 210for further separation.

The data in Table 11 were obtained by calculation using measured andcalculated thermodynamic properties.

TABLE 11 First First HF- 1225ye- First First rich rich Sec. Second ThirdThird Component Feed btm Dist phase phase Btm Dist btms dist of variable(10) (30) (40) (80) (90) (120) (130) (220) (230) HF, wt % 6.41 <1 ppm1.84 40.76 1.32 1 ppm 4.93 100.0 8.70 HFC- 51.33 99.95 1 ppm <1 ppm 1ppm 1 ppm <1 ppm <1 ppm <1 ppm 236cb, wt % HFC- 42.26 0.05 98.16 59.2498.68 100.0  95.07   1 ppm 91.30 1225ye, wt % Temp, ° C. 37.0 36.2 13.4−40.0 −40.0 15.5 12.1 60.7 12.1 Pres, psia 55.2 55.4 54.7 54.8 54.5 54.854.7 54.8 54.7

Example 10

This example shows how an HFC that forms an azeotrope with HF and afluoroolefin that is partially miscible with and forms an azeotrope withHF can both be separated from a mixture comprising HF, the HFC and thefluoroolefin by azeotropic distillation. If the HF-fluoroolefinazeotrope has a lower boiling point than the HF-HFC azeotrope, thefluoroolefin can be used as the entrainer to remove the HFC from themixture. The fluoroolefin and HF can be separated either by using thefluoroolefin as the entrainer, as shown in FIG. 6 and demonstrated inExample 8, or by using an added compound as the entrainer. The lattercase is covered by this example. Referring now to FIG. 7, the firstdistillation column (20), condenser (50), cooler (60), and decanter (70)in this embodiment operates identically to the similarly numberedequipment in Example 10 as just described. The HF-rich andfluoroolefin-rich liquid distillate fractions from the first column'sdecanter (70) are fed via streams 80 and 100 to distillation columns 210and 110 which recover purified HF and fluoroolefin, respectively. Theremaining portion of the process shown in FIG. 7, i.e., distillationcolumns 110 and 210, condensers 140 and 240, cooler 160, decanter 180,and all of their associated streams, have the same function and operatesimilarly to the same numbered equipment shown in FIG. 5 and describedin Example 8.

In other embodiments of the invention, (a) condensers 140 and 240 may becombined into a single unit, (b) coolers 60 and 160 can be combined intoa single unit and decanters 70 and 180 can be combined into a unit, asshown in FIG. 8, and (c) the three condensers 50, 140 & 240 can becombined into a single unit, coolers 60 and 160 can be combined into asingle unit and decanters 70 and 180 can be combined into a unit.

Example 11 Azeotropic Distillation for the Separation of HFC-1429mzyfrom HF without an Entrainer

Example 11 demonstrates that HF may be separated from HFC-1429mzy(1,1,1,3,4,4,5,5,5-nonafluoro-2-pentene) by azeotropic distillationwithout an added entrainer. HFC-1429mzy and HF form a minimum-boilingazeotrope that prevents their complete separation by ordinary fractionaldistillation. Referring now to FIG. 1, a composition comprising HF andHFC-1429mzy is fed to a first column 110 via stream 100. This firstcolumn contains 7 theoretical stages and is operated under appropriateconditions to approach the low-boiling HF/HFC-1429mzy azeotrope. BecauseHFC-1429mzy is being fed to this first column in excess of that neededto form the azeotrope with the HF, HFC-1429mzy is recovered as a productstream out the bottoms of the column via stream 120, while a compositionnear to the HF/HFC-1429mzy azeotrope is recovered as distillate viastream 130. Stream 130 is condensed in 140, mixed with the nearlyazeotropic composition recycled from the second column via stream 250and the combined stream is sub-cooled in cooler 160 and sent to decanter180 where the combined stream 170 separates into an HFC-1429mzy-rich(190) and an HF-rich (200) streams. Stream 190 is recycled to the topstage of the first column. Stream 200 is fed to the top stage of asecond distillation column 210, containing 12 theoretical stages andoperated under conditions to approach the HF/HFC-1429mzy azeotrope.Because HF is being fed to this second column in excess of that neededto form the low-boiling HF/HFC-1429mzy azeotrope, HF is recovered as aproduct stream out the bottoms of the column via stream 220 while acomposition close to the HF/HFC-1429mzy azeotrope is recovered asdistillate via stream 230. Stream 230 is condensed in 240, mixed withthe nearly azeotropic composition from the first column via stream 150and fed to cooler 160 and then decanter 180.

The data in Table 12 were calculated using measured and calculatedthermodynamic properties.

TABLE 12 First dist. HFC- col. 1429mzy Second bottom rich HF-rich dist.col. First (HFC- phase phase Bottom Component First dist. column 1429mzy(from (from Second (HF of variable col. feed distillate product)decanter) decanter) distillate product) Stream No. 100 130 120 190 200230 220 HF, wt % 3.6 20.8 1 ppm 4.4 65.7 23.2 100 HFC- 96.4 79.2 10095.6 34.3 76.8 1 ppm 1429mzy, wt % Temp, ° C. 30.0 49.1 75.7 40.0 40.048.8 66.7 Pres, psia 95 65 65 65 65 65 65 (kPa)

Example 12 Azeotropic Distillation for the Separation of PFC-1216 fromHF without an Entrainer

Example 12 demonstrates that HF may be separated from PFC-1216(hexafluoropropylene or HFP) by azeotropic distillation without an addedentrainer. HF and HFP form a minimum-boiling azeotrope that preventstheir complete separation by ordinary fractional distillation. Referringnow to FIG. 1, a composition comprising HF and HFP is fed to a firstcolumn 110 via stream 100. This first column contains 8 theoreticalstages and is operated under appropriate conditions to approach thelow-boiling HF/HFP azeotrope. Because HF is being fed to this firstcolumn in excess of that needed to form the azeotrope with the HFP, HFis recovered as a product stream out the bottoms of the column viastream 120, while a composition near to the HF/HFP azeotrope isrecovered as distillate via stream 130. Stream 130 is condensed in 140,mixed with the nearly azeotropic composition recycled from the secondcolumn via stream 250 and the combined stream is sub-cooled in cooler160 and sent to decanter 180 where the combined stream 170 separatesinto separate HF-rich 190 and HFP-rich 200 streams. Stream 190 isrecycled to the top stage of the first column. Stream 200 is fed to thetop stage of a second distillation column 210, containing 26 theoreticalstages and operated under conditions to approach the HF/HFP azeotrope.Because HFP is being fed to this second column in excess of that neededto form the low-boiling HF/HFP azeotrope, HFP is recovered as a productstream out the bottoms of the column via stream 220 while a compositionclose to the HF/HFP azeotrope is recovered as distillate via stream 230.Stream 230 is condensed in 240, mixed with the nearly azeotropiccomposition from the first column via stream 150 and fed to cooler 160and then decanter 180.

The data in Table 13 were calculated using measured and calculatedthermodynamic properties.

TABLE 13 First Second dist. col. HF rich HFP-rich dist. col. Firstbottom phase phase Bottom Component First dist. column (HF (from (fromSecond (HFP or variable col. feed distillate product) decanter)decanter) distillate product) Stream No. 100 130 120 190 200 230 220 HF,wt % 8.2 7.1 100 52.7 1.3 7.0 1 ppm HFP, wt % 91.8 92.9 10 ppm 47.3 98.793.0 100 Temp, ° C. 30.0 27.4 88.6 −25 −25.0 27.2 32.7 Pres, psia 165115 115 115 115 115 115 (kPa)

Example 13 Azeotropic Distillation for the Separation of HFC-1225zc andHF Using CFC-115 as the Entrainer

Example 13 demonstrates that HF and a fluoroolefin that form anazeotrope may be separated into essentially pure components byazeotropic distillation without requiring that the HF and thefluoroolefin be partially miscible. For illustration purposes,HFC-1225zc is used as the fluoroolefin in this example and CFC-115 isused as the azeotropic distillation entrainer. The CFC-115, HFC-1225zc,HF ternary mixture contains two minimum-boiling binary azeotropesbetween HF and HFC-1225zc and between HF and CFC-115 with the HF/CFC-115azeotrope having the lower boiling point. In addition, HF and CFC-115are only partially miscible.

Referring now to FIG. 2, a composition consisting of HF and HFC-1225zcis fed to a first column 110 containing 8 theoretical stages via stream100. An HF-rich and CFC-115-lean mixture is also fed to the top stage ofcolumn 110 via stream 190. Because the combined amount of HF in streams100 and 190 is in excess of that needed to form the low-boilingHF/HFC-1225zc azeotrope, column 110 is operated under conditions torecover the “excess” HF as a bottoms product essentially free of bothHFC-1225zc and CFC-115, which is removed via stream 120, and to producea distillate with a composition close to the HF/HFC-1225zc azeotrope,which is removed via stream 130. Stream 130 is condensed in condenser140, forming stream 150, and mixed with both the condensed distillatestream 250 from a second distillation column and, as needed, freshCFC-115 added via stream 260. Combined streams 150, 250, and 260 aresent first to cooler 160 and then to decanter 180 where the sub-cooledliquid stream 170 separates into HF-rich and CFC-1,5-rich liquid phasefractions which are removed via streams 190 and 200, respectively. TheHFC-1225zc present in the decanter primarily distributes into theCFC-115-rich liquid phase fraction. HF-rich stream 190 is recycled tothe first column as previously described. The HF-lean liquid phasefraction in the decanter is fed to the top stage of a seconddistillation column 210 containing 34 theoretical stages via stream 200.Because the concentration of HF in stream 200 is small enough for thecomposition of stream 200 to lie on the organic side of theHF/HFC-1225zc and HF/CFC-115 azeotropes and the distillation boundaryrunning between the two azeotropes, HFC-1225zc essentially free of bothHF and CFC-115 can be recovered as the bottoms product from column 210via stream 220. A ternary composition enriched in CFC-115 and depletedin HFC-1225zc relative to stream 200 is removed from the top of column210 as the distillate via stream 230. In the extreme, the composition ofdistillate 230 can approach the composition of the HF/CFC-115 azeotrope.Stream 230 is condensed in condenser 240, forming stream 250, and thencombined with streams 150 and 260 as previously described.

The data in Table 14 were calculated using measured and calculatedthermodynamic properties

TABLE 14 Entrainer- First HF-rich rich Second Second Component or Feedbtms First dist phase phase btms dist variable (100) (120) (130) (190)(200) (220) (230) HFC-1225zc, 86.84 10 ppm 90.51 26.37 60.86 100.0 45.72wt % HF, wt % 13.16 100.0 7.96 61.75 1.09 <1 ppm 1.52 CFC-115, wt % 0.0<1 ppm 1.53 11.89 38.05   1 ppm 52.76 Temp, ° C. 30.0 66.6 14.9 −25.0−25.0 18.2 7.1 Pres, psia 114.7 64.7 64.7 64.7 64.7 64.8 64.7

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

It is to be appreciated that certain features are, for clarity,described herein in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures that are, for brevity, described in the context of a singleembodiment, may also be provided separately or in any subcombination.Further, references to values stated in ranges include each and everyvalue within that range.

1. A process for separating a mixture comprising HF and fluoroolefin,said process comprising: a. feeding the composition comprising HF andfluoroolefin to a first distillation column; b. removing an azeotropecomposition comprising HF and fluoroolefin as a first distillate andeither i) HF or ii) fluoroolefin as a first column bottoms composition;c. condensing the first distillate to form 2 liquid phases, being i) anHF-rich phase and ii) a fluoroolefin-rich phase and separating said 2liquid phases in a decanter; and d. recycling a first liquid phaseenriched in the same compound that is removed as the first columnbottoms, said first liquid phase being either i) HF-rich phase or ii)fluoroolefin-rich phase, back to the first distillation column.
 2. Theprocess of claim 1, further comprising feeding a second liquid phase notrecycled in step (d), said second liquid phase being either i) HF-richphase or ii) fluoroolefin-rich phase, to a second distillation column,and recovering the compound not recovered in step (b) as the firstcolumn bottoms composition as the second column bottoms composition. 3.The process of claim 1, wherein said fluoroolefin is selected from thegroup consisting of: (i) fluoroolefins of the formula E- or Z—R¹CH═CHR²,wherein R¹ and R² are, independently, C₁ to C₆ perfluoroalkyl groups;(ii) cyclic fluoroolefins of the formula cyclo-[CX═CY(CZW)_(n)-],wherein X, Y, Z, and W, independently, are H or F, and n is an integerfrom 2 to 5; and (iii) fluoroolefins selected from the group consistingof: tetrafluoroethylene (CF₂═CF₂); hexafluoropropene (CF₃CF═CF₂);1,2,3,3,3-pentafluoro-1-propene (CHF═CFCF₃),1,1,3,3,3-pentafluoro-1-propene (CF₂═CHCF₃),1,1,2,3,3-pentafluoro-1-propene (CF₂═CFCHF₂),1,2,3,3-tetrafluoro-1-propene (CHF═CFCHF₂),2,3,3,3-tetrafluoro-1-propene (CH₂═CFCF₃), 1,3,3,3-tetrafluoro-1-propeneCHF═CHCF₃), 1,1,2,3-tetrafluoro-1-propene (CF₂═CFCH₂F),1,1,3,3-tetrafluoro-1-propene (CF₂═CHCHF₂),1,2,3,3-tetrafluoro-1-propene (CHF═CFCHF₂), 3,3,3-trifluoro-1-propene(CH₂═CHCF₃), 2,3,3-trifluoro-1-propene (CHF₂CF═CH₂);1,1,2-trifluoro-1-propene (CH₃CF═CF₂); 1,2,3-trifluoro-1-propene(CH₂FCF═CF₂); 1,1,3-trifluoro-1-propene (CH₂FCH═CF₂);1,3,3-trifluoro-1-propene (CHF₂CH═CHF);1,1,1,2,3,4,4,4-octafluoro-2-butene (CF₃CF═CFCF₃);1,1,2,3,3,4,4,4-octafluoro-1-butene (CF₃CF₂CF═CF₂);1,1,1,2,4,4,4-heptafluoro-2-butene (CF₃CF═CHCF₃);1,2,3,3,4,4,4-heptafluoro-1-butene (CHF═CFCF₂CF₃);1,1,1,2,3,4,4-heptafluoro-2-butene (CHF₂CF═CFCF₃);1,3,3,3-tetrafluoro-2-(trifluoromethyl)-1-propene ((CF₃)₂C═CHF);1,1,3,3,4,4,4-heptafluoro-1-butene (CF₂═CHCF₂CF₃);1,1,2,3,4,4,4-heptafluoro-1-butene (CF₂═CFCHFCF₃);1,1,2,3,3,4,4-heptafluoro-1-butene (CF₂═CFCF₂CHF₂);2,3,3,4,4,4-hexafluoro-1-butene (CF₃CF₂CF═CH₂);1,3,3,4,4,4-hexafluoro-1-butene (CHF═CHCF₂CF₃);1,2,3,4,4,4-hexafluoro-1-butene (CHF═CFCHFCF₃);1,2,3,3,4,4-hexafluoro-1-butene (CHF═CFCF₂CHF₂);1,1,2,3,4,4-hexafluoro-2-butene (CHF₂CF═CFCHF₂);1,1,1,2,3,4-hexafluoro-2-butene (CH₂FCF═CFCF₃);1,1,1,2,4,4-hexafluoro-2-butene (CHF₂CH═CFCF₃);1,1,1,3,4,4-hexafluoro-2-butene (CF₃CH═CFCHF₂);1,1,2,3,3,4-hexafluoro-1-butene (CF₂═CFCF₂CH₂F);1,1,2,3,4,4-hexafluoro-1-butene (CF₂═CFCHFCHF₂);3,3,3-trifluoro-2-(trifluoromethyl)-1-propene (CH₂═C(CF₃)₂);1,1,1,2,4-pentafluoro-2-butene (CH₂FCH═CFCF₃);1,1,1,3,4-pentafluoro-2-butene (CF₃CH═CFCH₂F);3,3,4,4,4-pentafluoro-1-butene (CF₃CF₂CH═CH₂);1,1,1,4,4-pentafluoro-2-butene (CHF₂CH═CHCF₃);1,1,1,2,3-pentafluoro-2-butene (CH₃CF═CFCF₃);2,3,3,4,4-pentafluoro-1-butene (CH₂═CFCF₂CHF₂);1,1,2,4,4-pentafluoro-2-butene (CHF₂CF═CHCHF₂);1,1,2,3,3-pentafluoro-1-butene (CH₃CF₂CF═CF₂);1,1,2,3,4-pentafluoro-2-butene (CH₂FCF═CFCHF₂);1,1,3,3,3-pentafluoro-2-methyl-1-propene (CF₂═C(CF₃)(CH₃));2-(difluoromethyl)-3,3,3-trifluoro-1-propene (CH₂═C(CHF₂)(CF₃));2,3,4,4,4-pentafluoro-1-butene (CH₂═CFCHFCF₃);1,2,4,4,4-pentafluoro-1-butene (CHF═CFCH₂CF₃);1,3,4,4,4-pentafluoro-1-butene (CHF═CHCHFCF₃);1,3,3,4,4-pentafluoro-1-butene (CHF═CHCF₂CHF₂);1,2,3,4,4-pentafluoro-1-butene (CHF═CFCHFCHF₂);3,3,4,4-tetrafluoro-1-butene (CH₂═CHCF₂CHF₂);1,1-difluoro-2-(difluoromethyl)-1-propene (CF₂═C(CHF₂)(CH₃));1,3,3,3-tetrafluoro-2-methyl-1-propene (CHF═C(CF₃)(CH₃));3,3-difluoro-2-(difluoromethyl)-1-propene (CH₂═C(CHF₂)₂);1,1,1,2-tetrafluoro-2-butene (CF₃CF═CHCH₃); 1,1,1,3-tetrafluoro-2-butene(CH₃CF═CHCF₃); 1,1,1,2,3,4,4,5,5,5-decafluoro-2-pentene(CF₃CF═CFCF₂CF₃); 1,1,2,3,3,4,4,5,5,5-decafluoro-1-pentene(CF₂═CFCF₂CF₂CF₃); 1,1,1,4,4,4-hexafluoro-2-(trifluoromethyl)-2-butene((CF₃)₂C═CHCF₃); 1,1,1,2,4,4,5,5,5-nonafluoro-2-pentene(CF₃CF═CHCF₂CF₃); 1,1,1,3,4,4,5,5,5-nonafluoro-2-pentene(CF₃CH═CFCF₂CF₃); 1,2,3,3,4,4,5,5,5-nonafluoro-1-pentene(CHF═CFCF₂CF₂CF₃); 1,1,3,3,4,4,5,5,5-nonafluoro-1-pentene(CF₂═CHCF₂CF₂CF₃); 1,1,2,3,3,4,4,5,5-nonafluoro-1-pentene(CF₂═CFCF₂CF₂CHF₂); 1,1,2,3,4,4,5,5,5-nonafluoro-2-pentene(CHF₂CF═CFCF₂CF₃); 1,1,1,2,3,4,4,5,5-nonafluoro-2-pentene(CF₃CF═CFCF₂CHF₂); 1,1,1,2,3,4,5,5,5-nonafluoro-2-pentene(CF₃CF═CFCHFCF₃); 1,2,3,4,4,4-hexafluoro-3-(trifluoromethyl)-1-butene(CHF═CFCF(CF₃)₂); 1,1,2,4,4,4-hexafluoro-3-(trifluoromethyl)-1-butene(CF₂═CFCH(CF₃)₂); 1,1,1,4,4,4-hexafluoro-2-(trifluoromethyl)-2-butene(CF₃CH═C(CF₃)₂); 1,1,3,4,4,4-hexafluoro-3-(trifluoromethyl)-1-butene(CF₂═CHCF(CF₃)₂); 2,3,3,4,4,5,5,5-octafluoro-1-pentene(CH₂═CFCF₂CF₂CF₃); 1,2,3,3,4,4,5,5-octafluoro-1-pentene(CHF═CFCF₂CF₂CHF₂); 3,3,4,4,4-pentafluoro-2-(trifluoromethyl)-1-butene(CH₂═C(CF₃)CF₂CF₃); 1,1,4,4,4-pentafluoro-3-(trifluoromethyl)-1-butene(CF₂═CHCH(CF₃)₂); 1,3,4,4,4-pentafluoro-3-(trifluoromethyl)-1-butene(CHF═CHCF(CF₃)₂); 1,1,4,4,4-pentafluoro-2-(trifluoromethyl)-1-butene(CF₂═C(CF₃)CH₂CF₃); 3,4,4,4-tetrafluoro-3-(trifluoromethyl)-1-butene((CF₃)₂CFCH═CH₂); 3,3,4,4,5,5,5-heptafluoro-1-pentene (CF₃CF₂CF₂CH═CH₂);2,3,3,4,4,5,5-heptafluoro-1-pentene (CH₂═CFCF₂CF₂CHF₂);1,1,3,3,5,5,5-heptafluoro-1-butene (CF₂═CHCF₂CH₂CF₃);1,1,1,2,4,4,4-heptafluoro-3-methyl-2-butene (CF₃CF═C(CF₃)(CH₃));2,4,4,4-tetrafluoro-3-(trifluoromethyl)-1-butene (CH₂═CFCH(CF₃)₂);1,4,4,4-tetrafluoro-3-(trifluoromethyl)-1-butene (CHF═CHCH(CF₃)₂);1,1,1,4-tetrafluoro-2-(trifluoromethyl)-2-butene (CH₂FCH═C(CF₃)₂);1,1,1,3-tetrafluoro-2-(trifluoromethyl)-2-butene (CH₃CF═C(CF₃)₂);1,1,1-trifluoro-2-(trifluoromethyl)-2-butene ((CF₃)₂C═CHCH₃);3,4,4,5,5,5-hexafluoro-2-pentene (CF₃CF₂CF═CHCH₃);1,1,1,4,4,4-hexafluoro-2-methyl-2-butene (CF₃C(CH₃)═CHCF₃);3,3,4,5,5,5-hexafluoro-1-pentene (CH₂═CHCF₂CHFCF₃);4,4,4-trifluoro-2-(trifluoromethyl)-1-butene (CH₂═C(CF₃)CH₂CF₃);1,1,2,3,3,4,4,5,5,6,6,6-dodecafluoro-1-hexene (CF₃(CF₂)₃CF═CF₂);1,1,1,2,2,3,4,5,5,6,6,6-dodecafluoro-3-hexene (CF₃CF₂CF═CFCF₂CF₃);1,1,1,4,4,4-hexafluoro-2,3-bis(trifluoromethyl)-2-butene((CF₃)₂C═C(CF₃)₂);1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene((CF₃)₂CFCF═CFCF₃);1,1,1,4,4,5,5,5-octafluoro-2-(trifluoromethyl)-2-pentene((CF₃)₂C═CHC₂F₅);1,1,1,3,4,5,5,5-octafluoro-4-(trifluoromethyl)-2-pentene((CF₃)₂CFCF═CHCF₃); 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene(CF₃CF₂CF₂CF₂CH═CH₂); 4,4,4-trifluoro-3,3-bis(trifluoromethyl)-1-butene(CH₂═CHC(CF₃)₃);1,1,1,4,4,4-hexafluoro-3-methyl-2-(trifluoromethyl)-2-butene((CF₃)₂C═C(CH₃)(CF₃));2,3,3,5,5,5-hexafluoro-4-(trifluoromethyl)-1-pentene(CH₂═CFCF₂CH(CF₃)₂); 1,1,1,2,4,4,5,5,5-nonafluoro-3-methyl-2-pentene(CF₃CF═C(CH₃)CF₂CF₃);1,1,1,5,5,5-hexafluoro-4-(trifluoromethyl)-2-pentene (CF₃CH═CHCH(CF₃)₂);3,4,4,5,5,6,6,6-octafluoro-2-hexene (CF₃CF₂CF₂CF═CHCH₃);3,3,4,4,5,5,6,6-octafluoro1-hexene (CH₂═CHCF₂CF₂CF₂CHF₂);1,1,1,4,4-pentafluoro-2-(trifluoromethyl)-2-pentene ((CF₃)₂C═CHCF₂CH₃);4,4,5,5,5-pentafluoro-2-(trifluoromethyl)-1-pentene (CH₂═C(CF₃)CH₂C₂F₅);3,3,4,4,5,5,5-heptafluoro-2-methyl-1-pentene (CF₃CF₂CF₂C(CH₃)═CH₂);4,4,5,5,6,6,6-heptafluoro-2-hexene (CF₃CF₂CF₂CH═CHCH₃);4,4,5,5,6,6,6-heptafluoro-1-hexene (CH₂═CHCH₂CF₂C₂F₅);1,1,1,2,2,3,4-heptafluoro-3-hexene (CF₃CF₂CF═CFC₂H₅);4,5,5,5-tetrafluoro-4-(trifluoromethyl)-1-pentene (CH₂═CHCH₂CF(CF₃)₂);1,1,1,2,5,5,5-heptafluoro-4-methyl-2-pentene (CF₃CF═CHCH(CF₃)(CH₃));1,1,1,3-tetrafluoro-2-(trifluoromethyl)-2-pentene ((CF₃)₂C═CFC₂H₅);1,1,1,2,3,4,4,5,5,6,6,7,7,7-tetradecafluoro-2-heptene(CF₃CF═CFCF₂CF₂C₂F₅);1,1,1,2,2,3,4,5,5,6,6,7,7,7-tetradecafluoro-3-heptene(CF₃CF₂CF═CFCF₂C₂F₅); 1,1,1,3,4,4,5,5,6,6,7,7,7-tridecafluoro-2-heptene(CF₃CH═CFCF₂CF₂C₂F₅); 1,1,1,2,4,4,5,5,6,6,7,7,7-tridecafluoro-2-heptene(CF₃CF═CHCF₂CF₂C₂F₅); 1,1,1,2,2,4,5,5,6,6,7,7,7-tridecafluoro-3-heptene(CF₃CF₂CH═CFCF₂C₂F₅); and1,1,1,2,2,3,5,5,6,6,7,7,7-tridecafluoro-3-heptene (CF₃CF₂CF═CHCF₂C₂F₅).4. The process of claim 3 wherein said fluoroolefin comprises at leastone compound selected from the group consisting of HFC-1225ye,HFC-1234ze, HFC-1234yf, and HFC-1243zf.
 5. The process of claim 1,wherein said fluoroolefin is present in a concentration greater than theazeotrope composition for hydrogen fluoride and said fluoroolefin, andwherein the first column bottoms composition is fluoroolefin essentiallyfree of hydrogen fluoride, and wherein said first liquid phase isenriched in fluoroolefin.
 6. The process of claim 5 further comprising:i. feeding the hydrogen fluoride-rich phase from the decanter to asecond distillation column, and ii. recovering hydrogen fluorideessentially free of fluoroolefin from the bottom of the seconddistillation column.
 7. The process of claim 6, further comprisingrecycling a second distillate composition to the two liquid phases inthe decanter.
 8. The process of claim 1, wherein hydrogen fluoride ispresent in a concentration greater than the azeotrope concentration forhydrogen fluoride and said fluoroolefin, and wherein the first columnbottoms composition is hydrogen fluoride essentially free offluoroolefin, and wherein said first liquid phase is enriched inhydrogen fluoride.
 9. The process of claim 8 further comprising: i.feeding the fluoroolefin-rich phase from the decanter to a seconddistillation column, and ii. recovering fluoroolefin essentially free ofhydrogen fluoride from the bottom of the second distillation column. 10.The process of claim 9, further comprising recycling a second distillatecomposition to the two liquid phases in the decanter.
 11. The process ofclaim 3, wherein said fluoroolefin is selected from the group consistingof: 1,1,1,4,4,4-hexafluorobut-2-ene;1,1,1,4,4,5,5,5-octafluoropent-2-ene;1,1,1,4,4,5,5,6,6,6-decafluorohex-2-ene;1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)pent-2-ene;1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene;1,1,1,4,4,5,5,6,6,7,7,7-dodecafluorohept-2-ene;1,1,1,4,4,5,6,6,6-nonafluoro-5-(trifluoromethyl)hex-2-ene;1,1,1,4,5,5,6,6,6-nonfluoro-4-(trifluoromethyl)hex-2-ene;1,1,1,5,5,5-hexafluoro-4,4-bis(trifluoromethyl)pent-2-ene;1,1,1,2,2,5,5,6,6,7,7,7-dodecafluorohept-3-ene;1,1,1,2,2,5,6,6,6-nonafluoro-5-(trifluoromethyl)hex-3-ene;1,1,1,4,4,5,5,6,6,7,7,8,8,8-tetradecafluorooct-2-ene;1,1,1,4,4,5,5,6,7,7,7-undecafluoro-6-(trifluoromethyl)hept-2-ene;1,1,1,5,5,6,6,6-octafluoro-4,4-bis(trifluoromethyl)hex-2-ene;1,1,1,2,2,5,5,6,6,7,7,8,8,8-tetradecafluorooct-3-ene;1,1,1,2,2,5,5,6,7,7,7-undecafluoro-6-(trifluoromethyl)hept-3-ene;1,1,1,2,2,5,6,6,7,7,7-undecafluoro-5-(trifluoromethyl)hept-3-ene;1,1,1,2,2,6,6,6-octafluoro-5,5-bis(trifluoromethyl)hex-3-ene;1,1,1,2,2,3,3,6,6,7,7,8,8,8-tetradecafluorooct-4-ene;1,1,1,2,5,6,6,6-octafluoro-2,5-bis(trifluoromethyl)hex-3-ene;1,1,1,2,5,5,6,6,7,7,7-undecafluoro-2-(trifluoromethyl)hept-3-ene;1,1,1,4,4,5,5,6,6,7,7,8,8,9,9,9-hexadecafluoronon-2-ene;1,1,1,4,5,5,6,6,7,7,8,8,8-tridecafluoro-4-(trifluoromethyl)hept-2-ene;1,1,1,6,6,6-octafluoro-4,4-bis(trifluoromethyl)hept-2-ene;1,1,1,2,2,5,5,6,6,7,7,8,8,9,9,9-hexadecafluoronon-3-ene;1,1,1,2,2,5,5,6,6,7,8,8,8-tridecafluoro-7-(trifluoromethyl)oct-3-ene;1,1,1,2,2,6,6,7,7,7-decafluoro-5,5-bis(trifluoromethyl)hept-3-ene;1,1,1,2,2,3,3,6,6,7,7,8,8,9,9,9-hexadecafluoronon-4-ene;1,1,1,2,2,3,3,6,6,7,8,8,8-tridecafluoro-7-(trifluoromethyl)oct-4-ene;1,1,1,2,2,3,3,6,7,7,8,8,8-tridecafluoro-6-(trifluoromethyl)oct-4-ene;1,1,1,5,5,6,6,7,7,7-decafluoro-2,2-bis(trifluoromethyl)hept-3-ene;1,1,1,2,5,5,6,6,7,7,8,8,8-tridecafluoro-2(trifluoromethyl)oct-3-ene;1,1,1,2,5,5,6,7,7,7-decafluoro-2,6-bis(trifluoromethyl)hept-3-ene;1,1,1,2,5,6,6,7,7,7-decafluoro-2,5-bis(trifluoromethyl)hept-3-ene;1,1,1,2,6,6,6-heptafluoro-2,5,5-tris(trifluoromethyl)hex-3-ene;1,1,1,2,2,5,5,6,6,7,7,8,8,9,9,10,10,10-octadecafluorodec-3-ene;1,1,1,2,2,5,6,6,7,7,8,8,9,9,9-pentadecafluoro-5-(trifluoromethyl)non-3-ene;1,1,1,2,2,6,6,7,7,8,8,8-dodecafluoro-5,5-bis(trifluoromethyl)oct-3-ene;1,1,1,2,2,3,3,6,6,7,7,8,8,9,9,10,10,10-octadecafluorodec-4-ene;1,1,1,2,2,3,3,6,6,7,7,8,9,9,9-pentadecafluoro-8-(trifluoromethyl)non-4-ene;1,1,1,2,2,3,3,7,7,8,8,8-dodecafluoro-6,6-bis(trifluoromethyl)oct-4-ene;1,1,1,2,5,5,6,6,7,7,8,8,9,9,9-pentadecafluoro-2-(trifluoromethyl)non-3-ene;1,1,1,2,5,5,6,6,7,8,8,8-dodecafluoro-2,7-bis(trifluoromethyl)oct-3-ene;1,1,1,2,6,6,7,7,7-nonafluoro-2,5,5-tris(trifluoromethyl)hept-3-ene;1,1,1,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluorodec-5-ene;1,1,1,2,3,3,6,6,7,7,8,8,9,9,9-pentadecafluoro-2-(trifluoromethyl)non-4-ene;1,1,1,2,2,3,6,6,7,7,8,8,9,9,9-pentadecafluoro-3-(trifluoromethyl)non-4-ene;1,1,1,5,5,6,6,7,7,8,8,8-dodecafluoro-2,2,-bis(trifluoromethyl)oct-3-ene;1,1,1,2,3,3,6,6,7,8,8,8-dodecafluoro-2,7-bis(trifluoromethyl)oct-4-ene;1,1,1,2,3,3,6,7,7,8,8,8-dodecafluoro-2,6-bis(trifluoromethyl)oct-4-ene;1,1,1,5,5,6,7,7,7-nonafluoro-2,2,6-tris(trifluoromethyl)hept-3-ene;1,1,1,2,2,3,6,7,7,8,8,8-dodecafluoro-3,6-bis(trifluoromethyl)oct-4-ene;1,1,1,2,2,3,6,7,7,8,8,8-dodecafluoro-3,6-bis(trifluoromethyl)oct-4-ene;1,1,1,5,6,6,7,7,7-nonafluoro-2,2,5-tris(trifluoromethyl)hept-3-ene; and1,1,1,6,6,6-hexafluoro-2,2,5,5-tetrakis(trifluoromethyl)hex-3-ene. 12.The composition of claim 3, wherein said fluoroolefin is selected fromthe group consisting of: 1,2,3,3,4,4-hexafluorocyclobutene;3,3,4,4-tetrafluorocyclobutene; 3,3,4,4,5,5,-hexafluorocyclopentene;1,2,3,3,4,4,5,5-octafluorocyclopentene; and1,2,3,3,4,4,5,5,6,6-decafluorocyclohexene.